# The 100 largest companies in the Yvelines department

Tamtam tracks 1,469 companies headquartered in the Yvelines department. This list ranks the 100 largest by number of employees on LinkedIn, led by Dassault Systèmes, Groupe PSA and Eiffage Énergie Systèmes. Their median headcount is 738. Half of them were founded in 1984 or later. The most common headquarters are Velizy-Villacoublay (23), Versailles (22) and Guyancourt (9).

The largest companies in Yvelines include major players in diverse sectors, predominantly large groups. Dassault Systèmes, for instance, pioneers virtual worlds for sustainable innovation. Groupe PSA (now Stellantis) is a leading automaker, while Eiffage Énergie Systèmes designs and maintains energy systems. ArianeGroup develops space launch systems, and SAVENCIA is a family-owned food group. These firms showcase a strong presence in engineering, manufacturing, and services.

A notable pattern is the concentration of headquarters in Vélizy-Villacoublay, home to several of the largest employers like Dassault Systèmes, Groupe PSA, and multiple Eiffage entities. This suggests a significant industrial and technological hub within the department, with a mix of very large established companies and some older, yet still substantial, enterprises such as Peugeot, founded in 1810.

🇫🇷 Yvelines · 100 companies · Updated Nov 11, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Dassault Systèmes](https://www.tamtam.ai/c/dassault-systemes) (3ds.com)<br>Pioneering virtual worlds since 1981, this company offers a platform enabling customers across industries to collaborate, imagine, and create sustainable innovations for real-life impact. | Software Development | 🇫🇷 Velizy-Villacoublay | 27,414 |  |
| 2 | [Groupe PSA](https://www.tamtam.ai/c/groupe-psa) (groupe-psa.com)<br>Leading automaker and mobility provider; now known as Stellantis. This entity is one of the world's foremost in vehicle manufacturing and mobility solutions. | Motor Vehicle Manufacturing | 🇫🇷 Velizy-Villacoublay | 16,153 |  |
| 3 | [Eiffage Énergie Systèmes](https://www.tamtam.ai/c/eiffage-energie-systemes) (eiffageenergiesystemes.com)<br>Designs, builds, operates, and maintains energy systems, offering innovative solutions in electrical, industrial, climatic, and energy engineering. | Environmental Services | 🇫🇷 Velizy-Villacoublay | 15,518 |  |
| 4 | [Peugeot](https://www.tamtam.ai/c/peugeot) (peugeot.com)<br>Offers customers exhilarating, quality driving experiences through racy design and uncompromised quality, adding excitement to every journey. | Motor Vehicle Manufacturing | 🇫🇷 Poissy | 9,490 | 1810 |
| 5 | [SAVENCIA](https://www.tamtam.ai/c/savencia) (savencia.com)<br>Family-owned food group valorizing milk and cocoa sectors for high-quality products, strong brands, meeting consumer expectations and supporting culinary professionals worldwide. | Food and Beverage Manufacturing | 🇫🇷 Viroflay | 9,109 |  |
| 6 | [Eiffage](https://www.tamtam.ai/c/eiffage) (eiffage.com)<br>Join a close-knit company valuing teamwork, innovation, and individuality to build a human-sized future, welcoming diverse talents to thrive | Construction | 🇫🇷 Velizy-Villacoublay | 7,684 |  |
| 7 | [SOCOTEC](https://www.tamtam.ai/c/socotec) (socotec.fr)<br>Provides services throughout the entire life cycle of built assets for compliance, extended lifespan, improved performance, and people’s safety in construction, infrastructure, and industry. | Environmental Services | 🇫🇷 Guyancourt | 7,326 | 1953 |
| 8 | [ArianeGroup](https://www.tamtam.ai/c/arianegroup) (ariane.group)<br>Designing, developing, manufacturing, and operating space launch systems and strategic missiles for space and defense sectors. | Aviation and Aerospace Component Manufacturing | 🇫🇷 Les Mureaux | 6,651 |  |
| 9 | [Bouygues Energies & Services](https://www.tamtam.ai/c/bouygues-energies-and-services) (bouygues-es.fr)<br>Bouygues Energies & Services is a key player in energy and digital transition, focusing on sustainable solutions and workforce development | Environmental Services | 🇫🇷 Guyancourt | 5,960 |  |
| 10 | [Eiffage Construction](https://www.tamtam.ai/c/eiffage-construction) (eiffageconstruction.com)<br>A leading European construction company specializing in development, real estate, construction, maintenance, and service works with a strong corporate culture | Construction | 🇫🇷 Velizy-Villacoublay | 5,174 |  |
| 11 | [Département des Yvelines](https://www.tamtam.ai/c/departement-des-yvelines) (yvelines.fr)<br>Local government providing social support, education, mobility, and territorial development services to improve daily life for residents. | Government Administration | 🇫🇷 Versailles | 4,000 | 1964 |
| 12 | [Eiffage Génie Civil](https://www.tamtam.ai/c/eiffage-genie-civil) (eiffagegeniecivil.com)<br>Specializing in civil engineering, this company designs, builds, maintains, and demolishes ambitious structures in France and internationally with a human perspective | Civil Engineering | 🇫🇷 Velizy-Villacoublay | 3,786 |  |
| 13 | [Eiffage Route](https://www.tamtam.ai/c/eiffage-route) (eiffageroute.com)<br>An expert in urban development, Eiffage Route contributes to improving the French road network through design, construction, maintenance, and various other projects | Construction | 🇫🇷 Velizy-Villacoublay | 3,480 |  |
| 14 | [KRYS GROUP](https://www.tamtam.ai/c/krys-group) (krys-group.com)<br>The company operates in optical and hearing health, distributing and manufacturing eyewear. It is a cooperative, focusing on human values and innovation for its products. | Retail | 🇫🇷 Bazainville | 3,310 | 1966 |
| 15 | [KNDS France](https://www.tamtam.ai/c/knds-france) (knds.com)<br>Designing, developing, producing armored vehicles, artillery, guns, turrets, ammunition, and robotic systems, with customer support, for armed forces land combat challenges. | Defense and Space Manufacturing | 🇫🇷 Versailles | 2,894 |  |
| 16 | [Novares Group](https://www.tamtam.ai/c/novares-group) (novaresteam.com)<br>Designs, manufactures complex plastic components and systems for the automotive industry, focusing on greener, lighter, and connected cars with intuitive interfaces. | Motor Vehicle Manufacturing | 🇫🇷 Velizy-Villacoublay | 2,833 | 1955 |
| 17 | [Académie de Versailles](https://www.tamtam.ai/c/academie-de-versailles) (ac-versailles.fr)<br>The company oversees education in four departments, serving 11 million students and managing 90,000 employees in various roles | Primary and Secondary Education | 🇫🇷 Versailles | 2,769 | 1972 |
| 18 | [HEC Paris](https://www.tamtam.ai/c/hec-paris) (hec.edu)<br>Offers diverse management education programs including Masters, MBA, PhD, and Executive Education for future leaders and current executives, with focus on education and research. | Higher Education | 🇫🇷 Jouy-en-Josas | 2,765 |  |
| 19 | [UVSQ Université de Versailles Saint-Quentin-en-Yvelines](https://www.tamtam.ai/c/uvsq-universite-de-versailles-saint-quentin-en-yvelines) (uvsq.fr)<br>Provides diverse higher education, conducts innovative research across various fields, and fosters technological advancements with strong industry and international partnerships. | Research Services | 🇫🇷 Versailles | 2,170 | 1991 |
| 20 | [Crédit Agricole Group Infrastructure Platform](https://www.tamtam.ai/c/credit-agricole-group-infrastructure-platform) (ca-groupinfrastructureplatform.fr)<br>Becoming a leading technology hub, developing new digital platforms, ensuring high security and confidentiality, positively impacting 54 million people. | IT Services and IT Consulting | 🇫🇷 Guyancourt | 2,035 | 2019 |
| 21 | [Bureau Vallée](https://www.tamtam.ai/c/bureau-vallee) (bureau-vallee.fr)<br>French retailer selling discounted stationery, office, tech, and furniture products to individuals and professionals across 240 stores and online. | Retail | 🇫🇷 Les Clayes-sous-Bois | 1,726 | 1990 |
| 22 | [Safran Landing Systems](https://www.tamtam.ai/c/safran-landing-systems) (safran-group.com)<br>Specializes in landing gear systems, providing innovative solutions for aircraft safety, performance, and maintenance in both commercial and military sectors. | Aviation and Aerospace Component Manufacturing | 🇫🇷 Velizy-Villacoublay | 1,717 |  |
| 23 | [Banque Populaire Val de France](https://www.tamtam.ai/c/banque-populaire-val-de-france) (banquepopulaire.fr)<br>This cooperative provides banking and insurance services, helping 550,000 clients and 132,700 members realize their personal and professional life projects. | Banking | 🇫🇷 Montigny-le-Bretonneux | 1,524 |  |
| 24 | [Groupe Léon Grosse](https://www.tamtam.ai/c/groupe-leon-grosse) (leongrosse.fr)<br>Specializes in large-scale construction and renovation projects including stadiums, transportation hubs, cultural sites, and sports facilities across France. | Construction | 🇫🇷 Versailles | 1,517 | 1881 |
| 25 | [LGM](https://www.tamtam.ai/c/lgm-velizy-villacoublay) (lgm.group)<br>The company offers technological, digital, and software engineering consulting, innovative solution design, and complex electronics production, supporting critical systems and industrial performance. | Engineering Services | 🇫🇷 Velizy-Villacoublay | 1,469 | 1991 |
| 26 | [Leasys](https://www.tamtam.ai/c/leasys) (leasys.com)<br>Offers long-term rental solutions and company fleet management systems across Europe for efficient, rational, safe, and sustainable mobility for businesses and individuals. | Financial Services | 🇫🇷 Poissy | 1,440 |  |
| 27 | [BTP Consultants](https://www.tamtam.ai/c/btp-consultants) (btp-consultants.fr)<br>Technical control, SPS coordination, and real estate diagnostics, with a focus on R&D, BIM, and off-site modular construction for various project needs. | Environmental Services | 🇫🇷 Montigny-le-Bretonneux | 1,418 | 1996 |
| 28 | [Fenwick-Linde](https://www.tamtam.ai/c/fenwick-linde) (bit.ly)<br>Listening to clients, creating innovative, tailored material handling solutions, with a focus on forklifts, intralogistics, robotics, and energy efficiency. | Industrial Machinery Manufacturing | 🇫🇷 Élancourt | 1,376 | 1985 |
| 29 | [Arquus](https://www.tamtam.ai/c/arquus) (arquus-defense.com)<br>Leading supplier of ground military vehicles to the French army, combining expertise from Renault Trucks Defense, ACMAT, and Panhard, with 130 years of automotive history. | Defense and Space Manufacturing | 🇫🇷 Versailles | 1,309 |  |
| 30 | [ERA IMMOBILIER France](https://www.tamtam.ai/c/era-immobilier-france) (eraimmobilier.com)<br>Established in 1971, this real estate franchise network is a leader in Europe with over 1,150 franchise locations in 39 countries, fostering a Gagnant / Gagnant (Win/Win) spirit | Real Estate | 🇫🇷 Versailles | 1,258 | 1971 |
| 31 | [Konica Minolta Business Solutions France](https://www.tamtam.ai/c/konica-minolta-business-solutions-france) (konicaminolta.fr)<br>Providing digital transformation solutions including imaging, cloud storage, IT services, and healthcare solutions Specializing in printing, AI technology, and eco-friendly initiatives | IT Services and IT Consulting | 🇫🇷 Carrières-sur-Seine | 1,148 | 1873 |
| 32 | [SDIS 78](https://www.tamtam.ai/c/sdis-78) (sdis78.fr)<br>Public establishment managing fire and rescue services in Yvelines, under mayors and prefects. Responsible for operations, personnel, and equipment. | Government Administration | 🇫🇷 Versailles | 1,061 | 1996 |
| 33 | [Nature et Découvertes](https://www.tamtam.ai/c/nature-et-decouvertes) (natureetdecouvertes.com)<br>Offers products for well-being, outdoor, home, games, and books. Provides concrete solutions for sustainable lifestyles, committed to living. A meaningful gift brand. | Retail | 🇫🇷 Versailles | 1,032 | 1990 |
| 34 | [SOURIAU-SUNBANK Connection Technologies by Eaton](https://www.tamtam.ai/c/souriau-sunbank-connection-technologies-by-eaton) (souriau.com)<br>An intelligent power management company focused on improving quality of life, protecting the environment, and helping customers manage power efficiently | Appliances, Electrical, and Electronics Manufacturing | 🇫🇷 Versailles | 965 |  |
| 35 | [ENSIO](https://www.tamtam.ai/c/ensio) (ensio.eu)<br>Specialized teams provide turnkey solutions for digital networks, energy networks, and maintenance services with a focus on sustainability and safety. | Telecommunications | 🇫🇷 Velizy-Villacoublay | 964 | 2008 |
| 36 | [Eiffage Rail](https://www.tamtam.ai/c/eiffage-rail) (eiffagerail.com)<br>Specializes in rail infrastructure construction, maintenance, and modernization, providing comprehensive solutions for railway networks and urban transit systems. | Rail Transportation | 🇫🇷 Velizy-Villacoublay | 938 |  |
| 37 | [SEPUR](https://www.tamtam.ai/c/sepur) (sepur.com)<br>With over 50 years of expertise, the company specializes in waste management and cleaning services for communities, including waste collection, recycling, and green waste processing | Environmental Services | 🇫🇷 Thiverval-Grignon | 937 | 1965 |
| 38 | [Jungheinrich France SAS](https://www.tamtam.ai/c/jungheinrich-france-sas) (jungheinrich.fr)<br>International leader in handling equipment, storage systems, and goods flow management. Offers forklifts, racking, services, and consulting for warehouse logistics needs. | Machinery Manufacturing | 🇫🇷 Velizy-Villacoublay | 909 |  |
| 39 | [CULLIGAN FRANCE](https://www.tamtam.ai/c/culligan-france) (culligan.fr)<br>Specialist in water treatment providing softeners, purifiers, and water fountains for homes, businesses, and communities ensuring quality water. | Consumer Services | 🇫🇷 Versailles | 862 |  |
| 40 | [Service d’infrastructure de la Défense](https://www.tamtam.ai/c/service-d-infrastructure-de-la-defense) (defense.gouv.fr)<br>Manages, builds, and maintains the French Ministry of Armed Forces' real estate, ensuring infrastructure support and energy control for military operations domestically and abroad. | Construction | 🇫🇷 Versailles | 850 | 2005 |
| 41 | [Stellantis &You, Sales and Services](https://www.tamtam.ai/c/stellantis-and-you-sales-and-services) (stellantisandyou.com)<br>Providing sales and customer services support, focusing on enhancing client experience and facilitating vehicle-related transactions and assistance. | Retail Motor Vehicles | 🇫🇷 Poissy | 838 | 2021 |
| 42 | [Lycée Sainte-Geneviève](https://www.tamtam.ai/c/lycee-sainte-genevieve) (bginette.com)<br>A private lycée in Versailles offering preparatory classes for French Grandes Écoles with high success rates at entrance exams Founded in 1854 | Higher Education | 🇫🇷 Versailles | 812 |  |
| 43 | [Emotors](https://www.tamtam.ai/c/emotors) (emotors.com)<br>Design and manufacturing of electric machines for on-road vehicles, providing solutions for propulsion and power generation in the automotive industry. | Motor Vehicle Manufacturing | 🇫🇷 Carrières-sous-Poissy | 811 | 2018 |
| 44 | [IT&COM](https://www.tamtam.ai/c/it-and-com) (itandcom.fr)<br>Specialist in computer science, professional training, and print and web communication services | Computer Networking Products | 🇫🇷 Orgeval | 795 | 2014 |
| 45 | [AXEO Services - La Poste Groupe](https://www.tamtam.ai/c/axeo-services-la-poste-groupe) (axeoservices.fr)<br>A leading network in France offering a wide range of home and business services, including cleaning, childcare, elderly care, security, and maintenance | Individual and Family Services | 🇫🇷 Le Mesnil-le-Roi | 795 | 2006 |
| 46 | [Clemessy Services](https://www.tamtam.ai/c/clemessy-services) (clemessy.com)<br>A leading French provider of industrial services, offering maintenance, engineering, and construction solutions for various industries worldwide | Industrial Machinery Manufacturing | 🇫🇷 Velizy-Villacoublay | 778 |  |
| 47 | [IVALIS Group](https://www.tamtam.ai/c/ivalis-group) (ivalisgroup.com)<br>Offers outsourced stocktaking, supply-chain audits, RFID solutions, product identification, geolocation services, and electronic shelf label installations for retail and supply-chain industries internationally. | Retail | 🇫🇷 Montigny-le-Bretonneux | 775 |  |
| 48 | [Carmat](https://www.tamtam.ai/c/carmat) (carmatsa.com)<br>Designs, manufactures, and markets the Aeson artificial heart, a physiological and self-regulated device for end-stage biventricular heart failure patients awaiting transplant. | Medical Equipment Manufacturing | 🇫🇷 Velizy-Villacoublay | 760 | 2008 |
| 49 | [Ville de Versailles](https://www.tamtam.ai/c/ville-de-versailles) (versailles.fr)<br>A historic city known for its palace and gardens, offering a vibrant local economy, employment opportunities in various fields, and a high quality of life | Government Administration | 🇫🇷 Versailles | 757 |  |
| 50 | [ENVEA Global](https://www.tamtam.ai/c/envea-global) (envea.global)<br>Provides advanced certified air quality and emissions monitoring solutions to help industries meet environmental targets and move towards net zero. Prevent harmful environmental pollution. | Industrial Machinery Manufacturing | 🇫🇷 Poissy | 738 | 1978 |
| 51 | [Credit Agricole Payment Services](https://www.tamtam.ai/c/credit-agricole-payment-services) (ca-payment-services.com)<br>Designing payment solutions for group entities, processing transactions, and developing innovative, secure service offerings with leading market standards. | Financial Services | 🇫🇷 Guyancourt | 736 | 1972 |
| 52 | [Château de Versailles](https://www.tamtam.ai/c/chateau-de-versailles) (chateauversailles.fr)<br>The company is a public institution maintaining and showcasing cultural heritage like the Versailles Palace, Trianon, gardens, and Marly domain They collaborate with various organizations | Museums, Historical Sites, and Zoos | 🇫🇷 Versailles | 732 | 1623 |
| 53 | [Schindler France](https://www.tamtam.ai/c/schindler-france) (schindler.fr)<br>Design, manufacture, install, maintain, and modernize elevators, escalators, moving walkways, and building mobility management products worldwide. | Transportation Equipment Manufacturing | 🇫🇷 Velizy-Villacoublay | 719 |  |
| 54 | [DTP](https://www.tamtam.ai/c/dtp) (dtp-bouygues-construction.com)<br>global construction developer builds structures and buildings worldwide, focusing on sustainable practices and low-carbon materials for diverse needs like housing, healthcare, and infrastructure. | Mining | 🇫🇷 Guyancourt | 717 |  |
| 55 | [DIAM Group · Retail & Merch Solutions](https://www.tamtam.ai/c/diam-group-retail-and-merch-solutions) (diaminter.com)<br>Providing end-to-end retail and merchandising services including design, production, installation, and after-sales support with global presence and sustainability focus. | Advertising Services | 🇫🇷 Les Mureaux | 688 |  |
| 56 | [Simply Market France](https://www.tamtam.ai/c/simply-market-france) (fr.whatjobs.com)<br>French supermarket chain providing fresh products and local service across three hundred locations through integrated or franchised stores with specialized management teams. | Retail Groceries | 🇫🇷 Jouy-en-Josas | 663 | 2009 |
| 57 | [Stellantis Financial Services](https://www.tamtam.ai/c/stellantis-financial-services) (stellantisfinancialservices.com)<br>Providing sustainable, innovative vehicle products and solutions worldwide, enhancing customer experience with accessible, affordable, and eco-friendly mobility options. | Financial Services | 🇫🇷 Poissy | 662 | 1919 |
| 58 | [Stellantis Finance & Services - CREDIPAR](https://www.tamtam.ai/c/stellantis-finance-and-services-credipar) (stellantis-finance-services.fr)<br>Offers financing solutions for purchasing and leasing vehicles across 11 Stellantis brands in France, plus associated services like insurance and maintenance. | Financial Services | 🇫🇷 Poissy | 651 | 1979 |
| 59 | [Hôpital de Poissy-Saint-Germain-en-Laye](https://www.tamtam.ai/c/hopital-de-poissy-saint-germain-en-laye) (ghtyvelinesnord.fr)<br>Public hospital in Yvelines, France, providing healthcare, education, and research across eight specialized care poles for all ages | Hospitals and Health Care | 🇫🇷 Poissy | 636 |  |
| 60 | [Ecole Supérieure des Techniques Aéronautiques et de Construction Automobile](https://www.tamtam.ai/c/ecole-superieure-des-techniques-aeronautiques-et-de-construction-automobile) (estaca.fr)<br>Educates engineers passionate about technology, addressing new mobility needs. Focuses on aeronautics, automotive, space, urban, and rail transport challenges for tomorrow. | Higher Education | 🇫🇷 Montigny-le-Bretonneux | 625 | 1925 |
| 61 | [Juridica](https://www.tamtam.ai/c/juridica) (juridica.fr)<br>Leading provider of legal protection insurance in France, offering innovative solutions for individuals and professionals by managing disputes and legal expenses | Insurance | 🇫🇷 Marly-le-Roi | 617 | 1981 |
| 62 | [Eiffage Métal](https://www.tamtam.ai/c/eiffage-metal) (eiffagemetal.com)<br>Specializing in turnkey metal construction, Eiffage Métal designs and builds building envelopes, facades, and complex multi-technical projects, with a focus on industrial and wind energy sectors | Construction | 🇫🇷 Velizy-Villacoublay | 607 |  |
| 63 | [SELL](https://www.tamtam.ai/c/sell) (sell-marketing.com)<br>A French independent company helps businesses master product information to optimize their sales strategy using the SELL BASE cloud platform | Software Development | 🇫🇷 Croissy-sur-Seine | 587 | 2006 |
| 64 | [DGF](https://www.tamtam.ai/c/dgf) (deliceetcreation.fr)<br>Supplies professional bakers and pastry chefs with high-quality raw materials, private label products, technical recipes, culinary training, and international pastry competition sponsorship. | Wholesale | 🇫🇷 Chanteloup-les-Vignes | 583 | 1986 |
| 65 | [CAR & DRIVER](https://www.tamtam.ai/c/car-and-driver)<br>A transportation/trucking/railroad company based in Versailles, France, specializing in providing efficient and reliable transportation solutions for clients | Truck Transportation | 🇫🇷 Versailles | 576 |  |
| 66 | [AGE D'OR Services](https://www.tamtam.ai/c/age-d-or-services) (agedorservices.com)<br>A leading home care network specializing in assisting seniors with a wide range of services to maintain their well-being and independence | Individual and Family Services | 🇫🇷 Le Mesnil-le-Roi | 568 | 1991 |
| 67 | [Ateme](https://www.tamtam.ai/c/ateme) (ateme.com)<br>The company specializes in video delivery solutions such as compression, packaging, cloud DVR, DAI, and CDN for content owners, broadcasters, and service providers | Telecommunications | 🇫🇷 Velizy-Villacoublay | 550 | 1991 |
| 68 | [Options](https://www.tamtam.ai/c/options) (options.fr)<br>Rental of catering equipment, tableware, food stations, and event furniture, plus design and production of beautiful event spaces. | Events Services | 🇫🇷 Les Mureaux | 519 | 1981 |
| 69 | [Pôle Emploi](https://www.tamtam.ai/c/pole-emploi) (pole-emploi.fr)<br>Distributor of IKON, a platform helping companies improve IT service performance and business activities through unified real-time monitoring and data management. | Government Administration | 🇫🇷 Plaisir | 511 |  |
| 70 | [Emitech Group](https://www.tamtam.ai/c/emitech-group) (emitech.fr)<br>Provides global testing services for automotive, aeronautic, and defense industries, including environmental, mechanical, EMC, and electrical tests on components, systems, and vehicles. | Business Consulting and Services | 🇫🇷 Montigny-le-Bretonneux | 510 | 1989 |
| 71 | [PESCHAUD INTERNATIONAL](https://www.tamtam.ai/c/peschaud-international) (peschaud-international.com)<br>Provides oilfield logistics services including rig-moves, transport, lifting, handling, and lodging in remote, challenging environments, utilizing specialized equipment and manpower. | Transportation, Logistics, Supply Chain and Storage | 🇫🇷 Saint-Germain-en-Laye | 497 | 1956 |
| 72 | [HexaWare](https://www.tamtam.ai/c/hexaware) (hexaware.net)<br>HexaWare offers tailored IT solutions and support to ensure continuity of your computer systems and constant access to your data | IT Services and IT Consulting | 🇫🇷 Versailles | 487 | 2003 |
| 73 | [CPAM des Yvelines](https://www.tamtam.ai/c/cpam-des-yvelines) (ameli.fr)<br>A private organization serving the CNAM for public service, protecting over 15 million individuals by implementing healthcare policies locally in Yvelines | Government Administration | 🇫🇷 Versailles | 480 | 1981 |
| 74 | [Advertising Agency](https://www.tamtam.ai/c/advertising-agency) (advertising-agency.fr)<br>Advertising Agency specializes in visual communication, marketing, and advertising consulting They create various online and offline communication materials for clients | Advertising Services | 🇫🇷 Sartrouville | 469 | 1989 |
| 75 | [Sodicam2 - Renault Group](https://www.tamtam.ai/c/sodicam2-renault-group) (sodicam2.fr)<br>Recruits, trains, and manages a sales force for automotive parts and accessories, ensuring performance and adaptation to market changes through employee development. | Motor Vehicle Manufacturing | 🇫🇷 Guyancourt | 440 | 1975 |
| 76 | [Fichet Group](https://www.tamtam.ai/c/fichet-group) (fichetgroup.fr)<br>Fichet Group offers creative and expert security solutions for businesses, banks, public administrations, retail, and homes, addressing evolving physical and cyber risks for a safer world. | Security and Investigations | 🇫🇷 Velizy-Villacoublay | 438 | 1998 |
| 77 | [Grand Paris Seine & Oise](https://www.tamtam.ai/c/grand-paris-seine-and-oise) (gpseo.fr)<br>management of a large urban and rural territory focusing on economic sectors, innovation, infrastructure, environment, and public services organization | Government Administration | 🇫🇷 Aubergenville | 429 | 2016 |
| 78 | [VITALREST](https://www.tamtam.ai/c/vitalrest) (vitalrest.com)<br>VITALREST is a family-owned company specializing in catering and hotel services for healthcare facilities, focusing on culinary expertise and customer satisfaction Offering various job opportunities nationwide | Food and Beverage Services | 🇫🇷 Saint-Germain-en-Laye | 428 | 2001 |
| 79 | [Ville de Mantes-la-Jolie](https://www.tamtam.ai/c/ville-de-mantes-la-jolie) (manteslajolie.fr)<br>City near a natural park balancing historic center, residential areas, economic development, urban planning, and upcoming RER line connection. | Government Administration | 🇫🇷 Mantes-la-Jolie | 420 |  |
| 80 | [Stellantis Financial Services UK, Germany and Austria](https://www.tamtam.ai/c/stellantis-financial-services-uk-germany-and-austria) (stellantisfinancialservices.com)<br>Provides vehicle finance solutions for brands within the Stellantis Group. Additionally, offers instant access and fixed-term deposit accounts in Germany. | Financial Services | 🇫🇷 Poissy | 411 | 1920 |
| 81 | [4D](https://www.tamtam.ai/c/4d) (us.4d.com)<br>A full-stack hybrid Low-Code Development platform that enables quick creation and deployment of web, mobile, and desktop applications for businesses worldwide | Software Development | 🇫🇷 Le Pecq | 405 | 1984 |
| 82 | [GROUPE LR TECHNOLOGIES](https://www.tamtam.ai/c/groupe-lr-technologies) (lrtechnologies.fr)<br>Provides human-centered engineering services, focusing on well-being, CSR, skills development, and recognition across various technology sectors like AI, cybersecurity, and critical software. | IT Services and IT Consulting | 🇫🇷 Versailles | 397 | 2014 |
| 83 | [Saphir Group](https://www.tamtam.ai/c/saphir-group) (quariq.com)<br>Provides Industry 4.0 solutions, industrial automation, MES/MOM, PLM, data and AI, OT security for manufacturers, from strategy to execution globally. | IT Services and IT Consulting | 🇫🇷 Montigny-le-Bretonneux | 380 | 2024 |
| 84 | [EOWIN](https://www.tamtam.ai/c/eowin) (eowin.com)<br>A leading content creation and management company with 30 years of experience, serving various industries worldwide in all aspects of information lifecycle | IT Services and IT Consulting | 🇫🇷 Guyancourt | 378 | 1989 |
| 85 | [COLAS DIGITAL SOLUTIONS](https://www.tamtam.ai/c/colas-digital-solutions) (colasdigitalsolutions.com)<br>Drives global IT and digital transformation projects for construction and transport infrastructure. Manages data centers, applications, IoT, Cloud, Big Data, and AI. | IT Services and IT Consulting | 🇫🇷 Velizy-Villacoublay | 377 | 1929 |
| 86 | [Ineo Defense](https://www.tamtam.ai/c/ineo-defense)<br>Provides technological solutions and services for defense and security, covering critical communications, electronic warfare, operational system protection, and site surveillance. | Defense and Space Manufacturing | 🇫🇷 Velizy-Villacoublay | 355 |  |
| 87 | [Les Diaconesses de Reuilly](https://www.tamtam.ai/c/les-diaconesses-de-reuilly) (lesdiaconesses.org)<br>Nonprofit organization providing healthcare, social support, inclusion for disabled, elderly care, end-of-life assistance, and healthcare professional training. | Health and Human Services | 🇫🇷 Versailles | 354 | 1841 |
| 88 | [Centre Hospitalier de Plaisir](https://www.tamtam.ai/c/centre-hospitalier-de-plaisir) (ch-plaisir.fr)<br>Provides diverse, specialized hospital and outpatient care in South Yvelines, including radiology, MRI, and CT scans, focusing on gerontological, medico-social, and mental health. | Hospitals and Health Care | 🇫🇷 Plaisir | 349 |  |
| 89 | [sophrologue](https://www.tamtam.ai/c/sophrologue)<br>Medical practice located in Rambouillet, France specializing in sophrology services to promote mental and physical well-being | Medical Practices | 🇫🇷 Rambouillet | 349 |  |
| 90 | [Egis en France](https://www.tamtam.ai/c/egis-en-france) (egis-group.com)<br>International consulting, construction engineering, and mobility services company. Designs and operates smart infrastructure and buildings addressing climate challenges for balanced and sustainable territorial development. | Civil Engineering | 🇫🇷 Guyancourt | 349 |  |
| 91 | [Centre hospitalier de Rambouillet](https://www.tamtam.ai/c/centre-hospitalier-de-rambouillet) (ch-rambouillet.fr)<br>Provides diverse medical services including imaging, surgery, cardiology, dialysis, emergency care, and laboratory support for local population. | Hospitals and Health Care | 🇫🇷 Rambouillet | 345 | 1731 |
| 92 | [Crous de Versailles](https://www.tamtam.ai/c/crous-de-versailles) (crous-versailles.fr)<br>State operator in charge of all student life aspects, serving 206,000 students in the Versailles academic region through 700 agents | Government Administration | 🇫🇷 Versailles | 344 | 1955 |
| 93 | [Mairie des Mureaux](https://www.tamtam.ai/c/mairie-des-mureaux) (lesmureaux.fr)<br>Provides administrative and local government services to residents and businesses in the Mureaux community within Yvelines, Île-de-France region. | Government Administration | 🇫🇷 Les Mureaux | 342 |  |
| 94 | [Eiffage Concessions](https://www.tamtam.ai/c/eiffage-concessions) (eiffageconcessions.com)<br>The company specializes in developing sustainable infrastructure projects, focusing on transport, renewable energy, urban facilities, and quality of life improvement for communities | Facilities Services | 🇫🇷 Velizy-Villacoublay | 338 |  |
| 95 | [STAR MARKET](https://www.tamtam.ai/c/star-market) (starmarket.com)<br>A food production company based in Maurepas, France, creating various food products for consumers. | Food and Beverage Manufacturing | 🇫🇷 Maurepas | 328 |  |
| 96 | [Woodford County Public Schools](https://www.tamtam.ai/c/woodford-county-public-schools) (beechwood.kyschools.us)<br>A highly reputable and long-standing educational institution known for its outstanding academic performance in the state | Primary and Secondary Education | 🇫🇷 Versailles | 324 | 1852 |
| 97 | [BATEG](https://www.tamtam.ai/c/bateg) (bateg.fr)<br>Specializes in constructing high-rise buildings, offices, and public facilities in Île-de-France, focusing on innovation and operational excellence. | Construction | 🇫🇷 Velizy-Villacoublay | 322 | 1982 |
| 98 | [Riva Acier](https://www.tamtam.ai/c/riva-acier) (rivaacier.com)<br>Over 45 years experience, seven industrial sites in France, leading steel long products manufacturer and largest scrap metal recycler in France. | Primary Metal Manufacturing | 🇫🇷 Gargenville | 312 | 1976 |
| 99 | [Airbus Defence and Space Cyber](https://www.tamtam.ai/c/airbus-defence-and-space-cyber) (cyber.airbus.com)<br>Designing, developing, integrating, and deploying reliable cyber security solutions for defense, governmental, and institutional customers, leveraging 30 years of expertise. | IT Services and IT Consulting | 🇫🇷 Élancourt | 308 |  |
| 100 | [BOUYGUES CONSTRUCTION IT](https://www.tamtam.ai/c/bouygues-construction-it) (bouygues-construction.fr)<br>Based in Guyancourt, France, provides information technology and services. This company focuses on delivering IT solutions for various needs. | IT Services and IT Consulting | 🇫🇷 Guyancourt | 307 |  |

## How this list is built

Every company on this list has a Tamtam company profile. The industry is the one the company gives on LinkedIn; categories such as SaaS or fintech are classified by Tamtam's AI from the company's website and LinkedIn page; and the headquarters city must match the company's own address. Companies are ranked by the number of employees on LinkedIn, and the list is refreshed every night. Classifications can be wrong, so treat the list as a starting point rather than an official ranking. Last updated Nov 11, 2026.

## More company lists in the Yvelines department

- [Multinational companies in the Yvelines department](https://www.tamtam.ai/l/multinational-companies-yvelines) (226)
- [Companies with in-house R&D in the Yvelines department](https://www.tamtam.ai/l/r-and-d-companies-yvelines) (160)
- [IT services companies in the Yvelines department](https://www.tamtam.ai/l/it-services-companies-yvelines) (121)
- [IT Services and IT Consulting companies in the Yvelines department](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-yvelines) (118)
- [Manufacturers in the Yvelines department](https://www.tamtam.ai/l/manufacturers-yvelines) (109)
- [Professional services firms in the Yvelines department](https://www.tamtam.ai/l/professional-services-firms-yvelines) (108)
- [Hardware manufacturers in the Yvelines department](https://www.tamtam.ai/l/hardware-companies-yvelines) (106)
- [Distributors and wholesalers in the Yvelines department](https://www.tamtam.ai/l/distributors-and-wholesalers-yvelines) (91)
- [Retail chains in the Yvelines department](https://www.tamtam.ai/l/retail-chains-yvelines) (89)
- [Consulting firms in the Yvelines department](https://www.tamtam.ai/l/consulting-firms-yvelines) (72)
- [Aerospace and defence companies in the Yvelines department](https://www.tamtam.ai/l/aerospace-and-defense-companies-yvelines) (65)
- [Public sector organisations in the Yvelines department](https://www.tamtam.ai/l/public-sector-organisations-yvelines) (65)
- [Software Development companies in the Yvelines department](https://www.tamtam.ai/l/software-development-companies-yvelines) (56)
- [Business Consulting and Services companies in the Yvelines department](https://www.tamtam.ai/l/business-consulting-and-services-companies-yvelines) (53)
- [Government Administration companies in the Yvelines department](https://www.tamtam.ai/l/government-administration-companies-yvelines) (51)
- [Construction companies in the Yvelines department](https://www.tamtam.ai/l/construction-companies-yvelines) (50)
- [Automotive manufacturers and suppliers in the Yvelines department](https://www.tamtam.ai/l/automotive-companies-yvelines) (49)
- [Motor Vehicle Manufacturing companies in the Yvelines department](https://www.tamtam.ai/l/motor-vehicle-manufacturing-companies-yvelines) (49)
- [SaaS companies in the Yvelines department](https://www.tamtam.ai/l/saas-companies-yvelines) (49)
- [Education providers in the Yvelines department](https://www.tamtam.ai/l/education-companies-yvelines) (46)
- [Industrial Machinery Manufacturing companies in the Yvelines department](https://www.tamtam.ai/l/industrial-machinery-manufacturing-companies-yvelines) (43)
- [Critical infrastructure operators in the Yvelines department](https://www.tamtam.ai/l/critical-infrastructure-operators-yvelines) (41)
- [Family-owned companies in the Yvelines department](https://www.tamtam.ai/l/family-owned-companies-yvelines) (36)
- [Environmental services companies in the Yvelines department](https://www.tamtam.ai/l/environmental-services-companies-yvelines) (35)

## The same list elsewhere in France

- [The largest companies in France](https://www.tamtam.ai/l/largest-companies-france) (90,813)
- [The largest companies in Île-de-France](https://www.tamtam.ai/l/largest-companies-ile-de-france) (36,143)
- [The largest companies in Auvergne-Rhône-Alpes](https://www.tamtam.ai/l/largest-companies-auvergne-rhone-alpes) (11,033)
- [The largest companies in Provence-Alpes-Côte d'Azur](https://www.tamtam.ai/l/largest-companies-provence-alpes-cote-dazur) (6,699)
- [The largest companies in Occitanie](https://www.tamtam.ai/l/largest-companies-occitanie) (5,769)
- [The largest companies in Grand Est](https://www.tamtam.ai/l/largest-companies-grand-est) (5,700)
- [The largest companies in Nouvelle-Aquitaine](https://www.tamtam.ai/l/largest-companies-nouvelle-aquitaine) (5,460)
- [The largest companies in the Hauts-de-Seine department](https://www.tamtam.ai/l/largest-companies-hauts-de-seine) (5,160)
- [The largest companies in the Rhône department](https://www.tamtam.ai/l/largest-companies-rhone) (4,813)
- [The largest companies in Hauts-de-France](https://www.tamtam.ai/l/largest-companies-hauts-de-france) (4,505)
- [The largest companies in Pays de la Loire](https://www.tamtam.ai/l/largest-companies-pays-de-la-loire) (4,269)
- [The largest companies in the Bouches-du-Rhône department](https://www.tamtam.ai/l/largest-companies-bouches-du-rhone) (3,318)
- [The largest companies in Brittany](https://www.tamtam.ai/l/largest-companies-brittany) (3,058)
- [The largest companies in the Nord department](https://www.tamtam.ai/l/largest-companies-nord) (2,806)
- [The largest companies in the Gironde department](https://www.tamtam.ai/l/largest-companies-gironde) (2,435)
- [The largest companies in the Haute-Garonne department](https://www.tamtam.ai/l/largest-companies-haute-garonne) (2,406)
- [The largest companies in Normandy](https://www.tamtam.ai/l/largest-companies-normandy) (2,380)
- [The largest companies in the Loire-Atlantique department](https://www.tamtam.ai/l/largest-companies-loire-atlantique) (2,046)
- [The largest companies in Bourgogne-Franche-Comté](https://www.tamtam.ai/l/largest-companies-bourgogne-franche-comte) (1,867)
- [The largest companies in Centre-Val de Loire](https://www.tamtam.ai/l/largest-companies-centre-val-de-loire) (1,701)
- [The largest companies in the Alpes-Maritimes department](https://www.tamtam.ai/l/largest-companies-alpes-maritimes) (1,538)
- [The largest companies in Paris](https://www.tamtam.ai/l/largest-companies-paris) (22,790)
- [The largest companies in Lyon](https://www.tamtam.ai/l/largest-companies-lyon) (2,679)
- [The largest companies in Toulouse](https://www.tamtam.ai/l/largest-companies-toulouse) (1,565)

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Source: https://www.tamtam.ai/l/largest-companies-yvelines