# Professional services firms headquartered in Boulogne-Billancourt

Tamtam tracks 102 professional services firms headquartered in Boulogne-Billancourt. This list ranks the 30 largest by number of employees on LinkedIn, led by ALTEN, Astek and Synergie France. Their median headcount is 603. Half of them were founded in 2004 or later.

The professional services sector in Boulogne-Billancourt is characterized by a strong presence of IT and engineering consulting firms. These companies, ranging from mid-sized to large enterprises, offer specialized expertise in digital transformation, IT services, and various engineering fields. Key players include ALTEN, which provides engineering and IT services, and Astek, focusing on sustainable digital transformation. BNP Paribas Real Estate offers comprehensive real estate services, while Synergie France specializes in HR services.

Several companies, such as Viveris and Apside, concentrate on information systems and technical computing. The presence of firms like Excelya and AIXIAL GROUP indicates a cluster of expertise in clinical development and pharmaceutical services. A common thread across many of these firms is their focus on high-value consulting and technical support for businesses seeking digital and technological advancement.

🇫🇷 Boulogne-Billancourt · 30 companies · Updated Nov 14, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [ALTEN](https://www.tamtam.ai/c/alten) (alten.com)<br>Provides engineering and IT services, supporting businesses in technological and sustainable transformation across various industries with high-level consultant-engineers. | Engineering Services | 🇫🇷 Boulogne-Billancourt | 38,710 | 1988 |
| 2 | [Astek](https://www.tamtam.ai/c/astek) (astekgroup.fr)<br>Supports clients with high-value service, deep technical expertise across technology, operations, and engineering, focusing on sustainable digital transformation with humans at the core. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 6,035 | 1988 |
| 3 | [Synergie France](https://www.tamtam.ai/c/synergie-france) (synergie.fr)<br>French leader in HR services: recruitment, training, and HR consulting Providing solutions in various sectors, emphasizing proximity, performance, and diversity | Human Resources Services | 🇫🇷 Boulogne-Billancourt | 4,804 |  |
| 4 | [BNP Paribas Real Estate](https://www.tamtam.ai/c/bnp-paribas-real-estate) (bnpparibas.com)<br>Offers comprehensive real estate services including property development, transactions, consulting, valuation, and property management across Europe, the Middle East, and Asia. | Real Estate | 🇫🇷 Boulogne-Billancourt | 4,173 | 1963 |
| 5 | [VISEO](https://www.tamtam.ai/c/viseo) (viseo.com)<br>Assists clients globally with digital and business transformation using advanced technology and industry expertise for productivity, innovation, and competitiveness. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 3,016 | 1999 |
| 6 | [Apside](https://www.tamtam.ai/c/apside) (apside.com)<br>Provides consulting, engineering in Information Systems, Technical and Scientific Computing, Automotive and Financial Engineering, for large French and European groups. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 2,300 | 1976 |
| 7 | [agap2](https://www.tamtam.ai/c/agap2) (agap2.com)<br>Global consulting firm specializing in industries and information systems, creating value for customers and consultants through innovation and extensive technical know-how. | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 2,075 | 2005 |
| 8 | [Davidson consulting](https://www.tamtam.ai/c/davidson-consulting) (davidson.fr)<br>A management consulting and technology company with over 2,000 employees, expanding internationally with a focus on employee well-being and creativity | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 1,843 | 2005 |
| 9 | [Rentokil Initial France](https://www.tamtam.ai/c/rentokil-initial-france) (rentokil-initial.com)<br>Pest control, hygiene solutions, cleaning, catering, interior landscaping, package delivery, and integrated facilities services for diverse customers. | Environmental Services | 🇫🇷 Boulogne-Billancourt | 979 | 1927 |
| 10 | [Viveris](https://www.tamtam.ai/c/viveris) (viveris.fr)<br>consulting and engineering company for information systems, technical computing, and embedded systems, providing support from definition to integration. | Software Development | 🇫🇷 Boulogne-Billancourt | 899 | 1986 |
| 11 | [Nomios Group](https://www.tamtam.ai/c/nomios-group) (nomios.com)<br>Designs, secures, and manages digital infrastructures, developing innovative cybersecurity and networking solutions through consulting, managed, and professional services for organizations. | Computer and Network Security | 🇫🇷 Boulogne-Billancourt | 887 | 2004 |
| 12 | [Bee Engineering](https://www.tamtam.ai/c/bee-engineering) (bee-eng.com)<br>Specializing in energy, processes, infrastructure, and transportation industries, we are a team of over 800 ambitious professionals based in 10 major cities | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 859 | 2010 |
| 13 | [Excelya](https://www.tamtam.ai/c/excelya) (excelya.com)<br>Provides comprehensive CRO, FSP, and Resourcing solutions to Biotech, Pharma, and Medical Device organizations, offering bespoke trial solutions across various therapeutic areas. | Pharmaceutical Manufacturing | 🇫🇷 Boulogne-Billancourt | 701 | 2014 |
| 14 | [AIXIAL GROUP](https://www.tamtam.ai/c/aixial-group) (aixialgroup.com)<br>Specialized partner in clinical development, providing comprehensive trial design, execution, functional service delivery, resources, and expert consulting for efficient clinical trials. | Research Services | 🇫🇷 Boulogne-Billancourt | 616 | 2004 |
| 15 | [PRIME ENGINEERING France](https://www.tamtam.ai/c/prime-engineering-france) (primeengineering.fr)<br>Engineering consulting firm, specializing in energy, infrastructure, and IT/telecom sectors, providing expertise and know-how since 2006. | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 603 | 2013 |
| 16 | [METSYS](https://www.tamtam.ai/c/metsys) (metsys.fr)<br>Advises clients on cybersecurity, infrastructure, and cloud solution design and implementation. Over 500 employees across France, 93.2M in revenue. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 435 | 2011 |
| 17 | [MEOGROUP](https://www.tamtam.ai/c/meogroup) (meogroup-partners.com)<br>Specializing in consulting services for a wide range of industries, providing operational solutions and recruitment services for companies of all sizes | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 428 | 2005 |
| 18 | [SARAWAK FRANCE](https://www.tamtam.ai/c/sarawak-france) (sarawak.fr)<br>Specializing in outsourced sales forces, animations in stores, and maximizing brand performance through motivated talents for consumer-centric results | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 392 | 1999 |
| 19 | [Audensiel](https://www.tamtam.ai/c/audensiel) (audensiel.com)<br>Supports clients in digital transformation projects, providing IT and business consulting, data/AI solutions, cybersecurity, and cloud/DevOps expertise. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 391 | 2013 |
| 20 | [ADENTIS](https://www.tamtam.ai/c/adentis) (adentis.fr)<br>High-tech consulting company developing software and embedded systems for digital TV, telecom, medical electronics, defense, and aeronautics. Research lab. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 362 | 2000 |
| 21 | [Concentrix Medica](https://www.tamtam.ai/c/concentrix-medica) (medica.concentrix.com)<br>Support pharmaceutical companies in promoting and selling products to healthcare professionals, plus patient coaching and disease management expertise. | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 327 | 2000 |
| 22 | [MEOTEC](https://www.tamtam.ai/c/meotec) (meotec.com)<br>Operational consulting firm providing support in project management, purchasing, supply chain, economic performance, quality, processes, IS, and technology. | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 325 | 2005 |
| 23 | [Lincoln France](https://www.tamtam.ai/c/lincoln-france) (lincoln.fr)<br>Offers data science and Modern BI expertise, consulting, and support for decision-making projects, utilizing predictive analysis and machine learning algorithms. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 316 | 1990 |
| 24 | [INGEVA](https://www.tamtam.ai/c/ingeva) (ingeva.fr)<br>Specialized in sustainable mobility engineering, this company supports public and private actors from design studies to project realization, including major rail and construction projects. | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 293 | 2014 |
| 25 | [Parthena Consultant](https://www.tamtam.ai/c/parthena-consultant) (parthena.com)<br>Integrates and supports management solutions like accounting, commercial management, payroll, CRM, and business management, offering services from analysis to hotline support. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 264 | 1990 |
| 26 | [ELITYS](https://www.tamtam.ai/c/elitys) (elitys.fr)<br>Elitys supports clients in Industry and Life Science projects, providing engineering expertise from industrialization to continuous improvement in collaboration with internal teams | Business Consulting and Services | 🇫🇷 Boulogne-Billancourt | 262 | 2005 |
| 27 | [ITS Services](https://www.tamtam.ai/c/its-services) (itsservices.fr)<br>ITS Services is a leading company in IT Infrastructure & Operations, offering expertise in Observability, SRE, and AIOps for accelerated time to market | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 240 | 1997 |
| 28 | [Cellenza](https://www.tamtam.ai/c/cellenza) (cellenza.com)<br>Provides IT consulting and implementation services, specializing in Microsoft Cloud solutions, including advisory, security, data, AI, and application development, aiding digital transformation. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 223 | 2011 |
| 29 | [GROUPE FACTORIA](https://www.tamtam.ai/c/groupe-factoria) (factoria-groupe.fr)<br>Providing specialized IT, telecom, printing, office furniture, and interactive screen solutions tailored for SMEs, professionals, and administrations in France. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 212 | 2006 |
| 30 | [Degetel](https://www.tamtam.ai/c/degetel) (degetel.com)<br>Provides digital transformation consulting, implements concrete solutions, simplifies user experience, and manages end-to-end business challenges for clients. | IT Services and IT Consulting | 🇫🇷 Boulogne-Billancourt | 180 | 1999 |

## 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 14, 2026.

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Source: https://www.tamtam.ai/l/professional-services-firms-boulogne-billancourt