# The 30 largest professional services firms in the Yvelines department
Tamtam tracks 108 professional services firms headquartered in the Yvelines department. This list ranks the 30 largest by number of employees on LinkedIn, led by SOCOTEC, LGM and BTP Consultants. Their median headcount is 284. Half of them were founded in 1991 or later. The most common headquarters are Guyancourt (7), Velizy-Villacoublay (5) and Versailles (5).
These companies in Yvelines are primarily large professional services firms, with a notable presence in IT and engineering. SOCOTEC provides services for built assets, LGM offers engineering consulting and complex electronics production, and BTP Consultants focuses on technical control and real estate diagnostics. Konica Minolta Business Solutions France specializes in digital transformation, while AXEO Services provides home and business services.
The data shows a concentration of IT Services and IT Consulting companies, with HexaWare, GROUPE LR TECHNOLOGIES, EOWIN, and act digital EMEA - Alter Solutions all based in Versailles or Guyancourt. This indicates a significant cluster of digital and technology-focused professional services within the department.
馃嚝馃嚪 Yvelines 路 30 companies 路 Updated Nov 12, 2026
| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [SOCOTEC](https://www.tamtam.ai/c/socotec) (socotec.fr)
Provides services throughout the entire life cycle of built assets for compliance, extended lifespan, improved performance, and people鈥檚 safety in construction, infrastructure, and industry. | Environmental Services | 馃嚝馃嚪 Guyancourt | 7,326 | 1953 |
| 2 | [LGM](https://www.tamtam.ai/c/lgm-velizy-villacoublay) (lgm.group)
The company offers technological, digital, and software engineering consulting, innovative solution design, and complex electronics production, supporting critical systems and industrial performance. | Engineering Services | 馃嚝馃嚪 Velizy-Villacoublay | 1,469 | 1991 |
| 3 | [BTP Consultants](https://www.tamtam.ai/c/btp-consultants) (btp-consultants.fr)
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 | 馃嚝馃嚪 Montigny-le-Bretonneux | 1,418 | 1996 |
| 4 | [Konica Minolta Business Solutions France](https://www.tamtam.ai/c/konica-minolta-business-solutions-france) (konicaminolta.fr)
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 | 馃嚝馃嚪 Carri猫res-sur-Seine | 1,148 | 1873 |
| 5 | [AXEO Services - La Poste Groupe](https://www.tamtam.ai/c/axeo-services-la-poste-groupe) (axeoservices.fr)
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 | 馃嚝馃嚪 Le Mesnil-le-Roi | 795 | 2006 |
| 6 | [Clemessy Services](https://www.tamtam.ai/c/clemessy-services) (clemessy.com)
A leading French provider of industrial services, offering maintenance, engineering, and construction solutions for various industries worldwide | Industrial Machinery Manufacturing | 馃嚝馃嚪 Velizy-Villacoublay | 778 | |
| 7 | [IVALIS Group](https://www.tamtam.ai/c/ivalis-group) (ivalisgroup.com)
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 | 馃嚝馃嚪 Montigny-le-Bretonneux | 775 | |
| 8 | [Emitech Group](https://www.tamtam.ai/c/emitech-group) (emitech.fr)
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 | 馃嚝馃嚪 Montigny-le-Bretonneux | 510 | 1989 |
| 9 | [HexaWare](https://www.tamtam.ai/c/hexaware) (hexaware.net)
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 | 馃嚝馃嚪 Versailles | 487 | 2003 |
| 10 | [Sodicam2 - Renault Group](https://www.tamtam.ai/c/sodicam2-renault-group) (sodicam2.fr)
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 | 馃嚝馃嚪 Guyancourt | 440 | 1975 |
| 11 | [VITALREST](https://www.tamtam.ai/c/vitalrest) (vitalrest.com)
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 | 馃嚝馃嚪 Saint-Germain-en-Laye | 428 | 2001 |
| 12 | [GROUPE LR TECHNOLOGIES](https://www.tamtam.ai/c/groupe-lr-technologies) (lrtechnologies.fr)
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 | 馃嚝馃嚪 Versailles | 397 | 2014 |
| 13 | [EOWIN](https://www.tamtam.ai/c/eowin) (eowin.com)
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 | 馃嚝馃嚪 Guyancourt | 378 | 1989 |
| 14 | [Egis en France](https://www.tamtam.ai/c/egis-en-france) (egis-group.com)
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 | 馃嚝馃嚪 Guyancourt | 349 | |
| 15 | [act digital EMEA - Alter Solutions](https://www.tamtam.ai/c/act-digital-emea-alter-solutions) (actdigital.com)
AI-first multinational technology company providing customized, scalable solutions with local agility and global expertise to create business value. | IT Services and IT Consulting | 馃嚝馃嚪 Versailles | 284 | 2006 |
| 16 | [CLF SATREM](https://www.tamtam.ai/c/clf-satrem) (clf-satrem.com)
Design, deploy, maintain innovative fire protection solutions for building, logistics, and industry sectors, ensuring safety and responsibility nationwide. | Facilities Services | 馃嚝馃嚪 Les Mureaux | 256 | 1989 |
| 17 | [Bouygues Construction Expertises Nucl茅aires](https://www.tamtam.ai/c/bouygues-construction-expertises-nucleaires)
Offers integrated, innovative, high-value solutions globally, covering all technical fields and the complete life cycle of nuclear infrastructure, including engineering, maintenance, and dismantling. | Civil Engineering | 馃嚝馃嚪 Guyancourt | 254 | |
| 18 | [In &Fi credits](https://www.tamtam.ai/c/in-and-fi-credits) (inandfi-credits.fr)
Network of banking and payment services intermediaries, providing optimal credit solutions to borrowers and aiming for French market leadership through franchisee recruitment. | Financial Services | 馃嚝馃嚪 Rambouillet | 251 | 2001 |
| 19 | [Cegedim Outsourcing](https://www.tamtam.ai/c/cegedim-outsourcing) (cegedim-outsourcing.fr)
Specializes in IT and BPO services with strong technological partnerships, providing high-level technical expertise and independent consulting. | IT Services and IT Consulting | 馃嚝馃嚪 Velizy-Villacoublay | 230 | |
| 20 | [SOCOTEC Formation](https://www.tamtam.ai/c/socotec-formation) (formation-socotec.fr)
Provides operational training in hygiene, health, safety, and QHSE for various industries including nuclear, with digital and onsite solutions. | Professional Training and Coaching | 馃嚝馃嚪 Guyancourt | 230 | |
| 21 | [TVH Consulting](https://www.tamtam.ai/c/tvh-consulting) (tvhconsulting.fr)
An international software company specializing in ERP solutions, systems integration, and industry-specific solutions for various verticals globally | IT Services and IT Consulting | 馃嚝馃嚪 Maisons-Laffitte | 221 | 2003 |
| 22 | [M茅diane Syst猫me](https://www.tamtam.ai/c/mediane-systeme) (medianesysteme.com)
Specializes in custom secure real-time operating systems, private 5G networks, embedded AI, cybersecurity, and industrial network solutions. | Software Development | 馃嚝馃嚪 Le Pecq | 213 | 1989 |
| 23 | [HOPITAL PRIVE DE L'OUEST PARISIEN](https://www.tamtam.ai/c/hopital-prive-de-l-ouest-parisien) (hopital-prive-de-l-ouest-parisien-trappes.ramsaysante.fr)
Multidisciplinary hospital providing high-quality medical-surgical care, established as the largest private Medicine Surgery Obstetrics (MCO) facility in Yvelines. | Hospitals and Health Care | 馃嚝馃嚪 Trappes | 202 | 1981 |
| 24 | [STORDATA](https://www.tamtam.ai/c/stordata) (stordata.fr)
Specializing in data management, STORDATA offers consulting, architecture, implementation, and support services, focusing on storage, backup, archiving, and virtualization solutions for clients' success | IT Services and IT Consulting | 馃嚝馃嚪 Versailles | 177 | 1988 |
| 25 | [LMF, une soci茅t茅 de SOCOTEC](https://www.tamtam.ai/c/lmf-une-societe-de-socotec) (lmf.fr)
Specialized training center providing certification for operating various equipment (CACES庐) and tailored solutions for specific needs, focusing on safety and hands-on learning with expert trainers | Professional Training and Coaching | 馃嚝馃嚪 Guitrancourt | 176 | 2001 |
| 26 | [Euriware](https://www.tamtam.ai/c/euriware) (euriware.fr)
A digital services company with 20 years of experience in demanding sectors like energy, industry, and defense, providing consulting, integration, and support services | IT Services and IT Consulting | 馃嚝馃嚪 Guyancourt | 136 | |
| 27 | [GROUPE EMILE DUFOUR SAS](https://www.tamtam.ai/c/groupe-emile-dufour-sas) (g-e-d.fr)
Engineering company specialized in electrical, electromechanical, and mechanical solutions for industries and businesses Dedicated team offers expertise for project management and process improvement | Mechanical Or Industrial Engineering | 馃嚝馃嚪 Mantes-la-Ville | 136 | 1936 |
| 28 | [Groupe Rouge Vif](https://www.tamtam.ai/c/groupe-rouge-vif) (grouperougevif.fr)
Advises on communication strategies, public and private territorial projects, and organizes events, focusing on human recognition and shared understanding across channels. | Advertising Services | 馃嚝馃嚪 Versailles | 114 | 1988 |
| 29 | [CLINACT](https://www.tamtam.ai/c/clinact) (multihealthgroup.com)
A leading Contract Research Organisation offering clinical research, biometrics, regulatory affairs, pharmacovigilance, e-tools, outsourcing, and professional training services to healthcare industries | Pharmaceutical Manufacturing | 馃嚝馃嚪 Velizy-Villacoublay | 107 | 1996 |
| 30 | [BETOM Ing茅nierie (BETOM Group)](https://www.tamtam.ai/c/betom-ingenierie-betom-group) (betom-ingenierie.fr)
Providing comprehensive technical engineering services including preliminary studies, design, project monitoring, and future building maintenance anticipation for clients. | Construction | 馃嚝馃嚪 Velizy-Villacoublay | 106 | |
## 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 12, 2026.
## More company lists in the Yvelines department
- [The largest companies in the Yvelines department](https://www.tamtam.ai/l/largest-companies-yvelines) (1,469)
- [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)
- [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
- [Professional services firms in France](https://www.tamtam.ai/l/professional-services-firms-france) (6,610)
- [Professional services firms in 脦le-de-France](https://www.tamtam.ai/l/professional-services-firms-ile-de-france) (3,377)
- [Professional services firms in Auvergne-Rh么ne-Alpes](https://www.tamtam.ai/l/professional-services-firms-auvergne-rhone-alpes) (711)
- [Professional services firms in the Hauts-de-Seine department](https://www.tamtam.ai/l/professional-services-firms-hauts-de-seine) (629)
- [Professional services firms in Provence-Alpes-C么te d'Azur](https://www.tamtam.ai/l/professional-services-firms-provence-alpes-cote-dazur) (433)
- [Professional services firms in the Rh么ne department](https://www.tamtam.ai/l/professional-services-firms-rhone) (400)
- [Professional services firms in Occitanie](https://www.tamtam.ai/l/professional-services-firms-occitanie) (399)
- [Professional services firms in Grand Est](https://www.tamtam.ai/l/professional-services-firms-grand-est) (316)
- [Professional services firms in Nouvelle-Aquitaine](https://www.tamtam.ai/l/professional-services-firms-nouvelle-aquitaine) (308)
- [Professional services firms in Hauts-de-France](https://www.tamtam.ai/l/professional-services-firms-hauts-de-france) (260)
- [Professional services firms in Pays de la Loire](https://www.tamtam.ai/l/professional-services-firms-pays-de-la-loire) (253)
- [Professional services firms in the Bouches-du-Rh么ne department](https://www.tamtam.ai/l/professional-services-firms-bouches-du-rhone) (249)
- [Professional services firms in the Haute-Garonne department](https://www.tamtam.ai/l/professional-services-firms-haute-garonne) (208)
- [Professional services firms in the Nord department](https://www.tamtam.ai/l/professional-services-firms-nord) (178)
- [Professional services firms in Brittany](https://www.tamtam.ai/l/professional-services-firms-brittany) (167)
- [Professional services firms in the Loire-Atlantique department](https://www.tamtam.ai/l/professional-services-firms-loire-atlantique) (158)
- [Professional services firms in the Gironde department](https://www.tamtam.ai/l/professional-services-firms-gironde) (151)
- [Professional services firms in Normandy](https://www.tamtam.ai/l/professional-services-firms-normandy) (114)
- [Professional services firms in the Ille-et-Vilaine department](https://www.tamtam.ai/l/professional-services-firms-ille-et-vilaine) (94)
- [Professional services firms in Paris](https://www.tamtam.ai/l/professional-services-firms-paris) (2,241)
- [Professional services firms in Lyon](https://www.tamtam.ai/l/professional-services-firms-lyon) (265)
- [Professional services firms in Toulouse](https://www.tamtam.ai/l/professional-services-firms-toulouse) (139)
- [Professional services firms in Marseille](https://www.tamtam.ai/l/professional-services-firms-marseille) (123)
- [Professional services firms in Boulogne-Billancourt](https://www.tamtam.ai/l/professional-services-firms-boulogne-billancourt) (102)
## The same list elsewhere
- [Professional services firms in the world](https://www.tamtam.ai/l/professional-services-firms-in-the-world) (24,737)
- [Professional services firms in Europe](https://www.tamtam.ai/l/professional-services-firms-in-europe) (13,698)
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Source: https://www.tamtam.ai/l/professional-services-firms-yvelines