The companies listed in Hauts-de-Seine are primarily large professional services firms, with a strong emphasis on engineering, IT consulting, and environmental services. These companies provide specialized expertise across various industries, from digital transformation to risk management.
Among them, ALTEN provides engineering and IT services, ELIS offers circular services for hygiene and well-being, Equans France designs solutions for energy and digital transitions, and Devoteam specializes in AI-driven tech consulting. Many of these firms, such as Apave and ELIS, have long histories, indicating established players in their respective fields. The presence of multiple headquarters in Boulogne-Billancourt, Courbevoie, and Levallois-Perret suggests these cities are significant hubs for professional services within the department.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 | 38,710 | ||||
| 2 | 15,750 | ||||
| 3 |
Altrancapgemini-engineering.com
Altran, now Capgemini Engineering, offers engineering services Follow them on LinkedIn for updates and insights |
11,652 | |||
| 4 |
Equans Franceequans.fr
Designs, installs, and delivers bespoke solutions optimizing equipment and usage for businesses, local authorities, and industrial players in energy, industrial, and digital transitions. |
11,029 | |||
| 5 |
Devoteamdevoteam.com
AI-driven tech consulting firm specializing in cloud platforms, cyber, data, and sustainability, guiding businesses through sustainable digital transformation to deliver value. |
10,274 | |||
| 6 | 9,778 | ||||
| 7 |
Forvis Mazars Groupforvismazars.com
International partnership delivering audit, tax, and advisory services across one hundred countries and territories through an integrated global professional services network. |
9,534 | |||
| 8 |
Assystemassystem.com
Independent nuclear engineering company accelerating energy transition, developing nuclear and renewable energies, power grids, hydrogen projects, and low-carbon transport. |
8,143 | |||
| 9 |
Actemiumactemium.com
Delivering bespoke solutions and services globally, combining local business unit expertise to create value throughout the industrial life cycle for a sustainable world. |
6,718 | |||
| 10 |
Astekastekgroup.fr
Supports clients with high-value service, deep technical expertise across technology, operations, and engineering, focusing on sustainable digital transformation with humans at the core. |
6,035 | |||
| 11 |
TRIGOtrigo-group.com
Provides comprehensive quality solutions and management services for automotive, aerospace, and transport industries, addressing supply chain challenges globally with local expertise. |
5,771 | |||
| 12 |
Vulcain Engineering Groupvulcain-eng.com
Provides engineering consulting and project solutions for energy and environmental sectors, delivering technical assistance, expertise, and project management globally. |
5,234 | |||
| 13 |
Securitas Francesecuritas.fr
Provides private security services including surveillance and guarding, tailored to meet specific business security needs and requirements. |
5,060 | |||
| 14 |
Synergie Francesynergie.fr
French leader in HR services: recruitment, training, and HR consulting Providing solutions in various sectors, emphasizing proximity, performance, and diversity |
4,804 | |||
| 15 |
BNP Paribas Real Estatebnpparibas.com
Offers comprehensive real estate services including property development, transactions, consulting, valuation, and property management across Europe, the Middle East, and Asia. |
4,173 | |||
Want more companies than this list?This page shows the largest ones only. Connect to Tamtam to see every company that matches, filter by size, industry or growth, and reach their decision-makers. | |||||
| 16 |
PwC Francepwc.fr
Offers consulting, audit, legal, and tax expertise, blending technology with multidisciplinary knowledge to accelerate sustainable business transformation for organizations. |
4,109 | |||
| 17 |
Scalianscalian.com
A global company founded in 1989 with 3 business lines focusing on Digital Transformation, Digital Systems, and Operations Performance across various countries |
4,098 | |||
| 18 |
Manpower Francemanpower.fr
Offers recruitment solutions through a network of specialized consultants and provides flexible interim staffing solutions across various sectors to companies of all sizes. |
3,839 | |||
| 19 |
Leytonleyton.com
International consulting firm helps businesses leverage financial incentives for growth and long-lasting performance by simplifying access to complex benefits. |
3,243 | |||
| 20 |
Dekra Francedekra.fr
Inspection, certification, risk management, audits, training, and consulting services for automotive, transport, industry, environment, and safety sectors. |
3,188 | |||
| 21 | 3,016 | ||||
| 22 |
VINCI Energies en France
Accelerating environmental transition in France by focusing on energy and digital transformations for factories, buildings, cities, and energy/transport infrastructure with innovative solutions |
2,953 | |||
| 23 |
SE Advisory Servicesseadvisoryservices.com
Helps organizations achieve sustainability, energy, and digitalization goals through expertise, global implementation, and AI-powered software, turning challenges into advantages. |
2,948 | |||
| 24 | 2,854 | ||||
| 25 |
Vitalliancevitalliance.fr
Provides comprehensive home care support for individuals experiencing loss of autonomy, assisting with daily living, administrative tasks, and social interaction, including inclusive housing projects. |
2,702 | |||
| 26 |
Sogetrelsogetrel.fr
A leader in digital transformation, specializing in digital infrastructure services and connected devices to enhance citizens' lives, business performance, and sustainable development |
2,581 | |||
| 27 |
UFF - Conseil en gestion de patrimoineuff.net
Established in 1968, this bank provides wealth management services for individuals, businesses, executives, and professional athletes Offers a range of financial products and solutions |
2,466 | |||
| 28 |
Grant-Thornton Francegrantthornton.fr
Provides audit, financial advisory, operational consulting, legal and tax advice, and sustainable transformation services to French businesses. |
2,342 | |||
| 29 |
Apsideapside.com
Provides consulting, engineering in Information Systems, Technical and Scientific Computing, Automotive and Financial Engineering, for large French and European groups. |
2,300 | |||
| 30 | 2,281 | ||||
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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 Hauts-de-Seine department
- The largest companies in the Hauts-de-Seine department 5,160
- Multinational companies in the Hauts-de-Seine department 1,231
- IT services companies in the Hauts-de-Seine department 737
- IT Services and IT Consulting companies in the Hauts-de-Seine department 706
- Consulting firms in the Hauts-de-Seine department 563
- Companies with in-house R&D in the Hauts-de-Seine department 510
- SaaS companies in the Hauts-de-Seine department 389
- Business Consulting and Services companies in the Hauts-de-Seine department 304
- Software Development companies in the Hauts-de-Seine department 301
- Retail chains in the Hauts-de-Seine department 292
- Manufacturers in the Hauts-de-Seine department 285
- Advertising Services companies in the Hauts-de-Seine department 281
- Marketing and communications agencies in the Hauts-de-Seine department 235
- Subscription businesses in the Hauts-de-Seine department 228
- Hardware manufacturers in the Hauts-de-Seine department 199
- Financial services firms in the Hauts-de-Seine department 198
- Companies with a mobile app in the Hauts-de-Seine department 189
- Critical infrastructure operators in the Hauts-de-Seine department 169
- AI companies in the Hauts-de-Seine department 159
- Education providers in the Hauts-de-Seine department 159
- Cybersecurity companies in the Hauts-de-Seine department 154
- Distributors and wholesalers in the Hauts-de-Seine department 154
- Recruitment and staffing agencies in the Hauts-de-Seine department 152
- Energy companies in the Hauts-de-Seine department 144
The same list elsewhere in France
- Professional services firms in France 6,610
- Professional services firms in 脦le-de-France 3,377
- Professional services firms in Auvergne-Rh么ne-Alpes 711
- Professional services firms in Provence-Alpes-C么te d'Azur 433
- Professional services firms in the Rh么ne department 400
- Professional services firms in Occitanie 399
- Professional services firms in Grand Est 316
- Professional services firms in Nouvelle-Aquitaine 308
- Professional services firms in Hauts-de-France 260
- Professional services firms in Pays de la Loire 253
- Professional services firms in the Bouches-du-Rh么ne department 249
- Professional services firms in the Haute-Garonne department 208
- Professional services firms in the Nord department 178
- Professional services firms in Brittany 167
- Professional services firms in the Loire-Atlantique department 158
- Professional services firms in the Gironde department 151
- Professional services firms in Normandy 114
- Professional services firms in the Yvelines department 108
- Professional services firms in the Ille-et-Vilaine department 94
- Professional services firms in Paris 2,241
- Professional services firms in Lyon 265
- Professional services firms in Toulouse 139
- Professional services firms in Marseille 123
- Professional services firms in Boulogne-Billancourt 102