This selection of critical infrastructure operators in Seine-Saint-Denis includes large groups and public entities. Veolia, with over 50,000 employees, specializes in environmental services like water, waste, and energy solutions. SNCF Réseau manages national railway infrastructure, while SNCF Voyageurs handles passenger transportation. GRDF operates Europe's largest gas distribution network, and BNP Paribas - Securities Services provides asset servicing solutions to financial markets. ACOSS supports employers and entrepreneurs in social protection financing.
A notable pattern is the strong presence of companies in essential public services and utilities. Environmental services, rail transportation, and government administration are particularly well-represented. Many of these organizations, such as Veolia and Generali France, have long histories, indicating established operations within the department.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
Veoliaveolia.com
Works to build environmental security, cleans up pollution, reduces carbon emissions, and regenerates resources through water, waste, and energy solutions. |
50,280 | |||
| 2 |
SNCF Réseausncf-reseau.fr
public entity managing national railway infrastructure, unifying previous services, ensuring clear governance, and coordinating with railway operator SNCF Mobilités. |
23,115 | |||
| 3 |
SNCF Voyageurssncf-voyageurs.com
SNCF Voyageurs is a subsidiary of the SNCF Group responsible for passenger transportation on the French national railway network |
18,564 | |||
| 4 |
Veolia | Water Techveoliawatertechnologies.com
Provides global water technology expertise, ensuring performance, sustainability, and resource protection for communities and industries through advanced solutions and services. |
13,064 | |||
| 5 | 7,313 | ||||
| 6 |
BNP Paribas - Securities Servicescib.bnpparibas
Provides multi-asset post-trade, asset servicing solutions to financial market participants, corporates, and issuers, with an extensive global custody network. |
6,196 | |||
| 7 |
Veolia | Franceveolia.fr
Provides specialized services for water management, waste treatment, and energy recovery to help cities and industries preserve, access, and renew essential resources. |
6,110 | |||
| 8 |
ACOSSlinkedin.com
A national organization supports employers and entrepreneurs by advising, informing, and streamlining services, ensuring social protection financing, and promoting responsibility, solidarity, and equity |
3,000 | |||
| 9 |
Agence Régionale de Santé Ile-de-Francelinktr.ee
Implements regional health policy, covering prevention, care, and medico-social support, developed in consultation with professionals and users for efficiency and transparency. |
2,332 | |||
| 10 | 1,677 | ||||
| 11 |
Société des grands projetssocietedesgrandsprojets.fr
Development and management of decarbonized transport projects including new metro lines and regional express services to improve daily mobility. |
1,367 | |||
| 12 |
Urssaf Ile-de-Francelasecurecrute.fr
Collection and redistribution of social security contributions ensuring workers' social protection and supporting entrepreneurs with compliance and service. |
1,142 | |||
| 13 |
GEH - Groupe Europe Handlinggeh.aero
Provides innovative, efficient airport services, encompassing passenger and baggage handling, ground support, traffic operations, cargo management, and maintenance for airlines worldwide since 1994. |
911 | |||
| 14 |
DHL Express Francedhlexpress.fr
Global leader in international express transport providing carbon-conscious logistics, parcel delivery, and supply chain solutions for business and individual customers through extensive networks. |
828 | |||
| 15 | 645 | ||||
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| 16 |
SNCF Voyageurs Matérielsncf-voyageurs.com
Manages maintenance for nearly 17,000 rolling stock units. Provides high-level industrial performance, ensuring safety, quality, and technical expertise for internal and external clients. |
606 | |||
| 17 |
DB Cargo Francedbcargo.com
Provides diverse rail freight solutions from single wagons to full trains, including combined transport across France and to bordering countries for various goods. |
527 | |||
| 18 |
GROUPE CORIANCEgroupe-coriance.fr
Providing high-performance and cost-effective energy solutions while minimizing environmental impact, specializing in renewable energy sources like geothermal, biomass, and cogeneration |
509 | |||
| 19 |
Grand Paris Expressgrandparisexpress.fr
Public organization creating the new Grand Paris automated metro, responsible for designing, developing, and building the network's infrastructure and stations |
454 | |||
| 20 |
Crédit Agricole La Réunion - Mayottecredit-agricole.fr
A mutual bank supporting individuals, professionals, farmers, and associations with their projects in Réunion and Mayotte for over 72 years |
442 | |||
| 21 |
Veolia | Énergie & Décarbonationveolia.fr
Provides energy audits, renewable production, smart cooling networks, and performance optimization to ensure sovereignty and environmental footprint reduction for industries and local territories. |
429 | |||
| 22 |
UGECAM Ile-de-Francegroupe-ugecam.fr
Non-profit organization providing comprehensive health and social care services, supporting rehabilitation and reintegration for individuals with disabilities across various age groups and needs. |
419 | |||
| 23 |
ASL Airlines Franceaslairlines.fr
Provides passenger flights for tour operators, regular international routes, VIP charters, and dedicated aircraft. Also offers express and on-demand cargo services. |
394 | |||
| 24 | 
CENTRE HOSPITALIER DE MONTREUIL HOPITAL ANDRE GREGOIREght-gpne.fr
Medical practice company based in Montreuil, France, providing a range of healthcare services at Hôpital André Grégoire |
388 | |||
| 25 |
Netcom Groupnetcom-group.fr
Operator providing fixed, mobile, and internet solutions for businesses, emphasizing customer satisfaction, transparency, and eco-responsible products. |
302 | |||
| 26 |
GHT Grand Paris Nord-Estght-gpne.fr
Three hospitals in Seine-Saint-Denis providing specialized, teaching, and research healthcare services with over 6000 professionals ensuring coordinated, quality patient care. |
297 | |||
| 27 |
Centre Hospitalier de Saint-Denisch-stdenis.fr
Public hospital offering medical care without discrimination, with a focus on multicultural patient care Provides various medical specialties, including emergency services and perinatal care |
293 | |||
| 28 |
LOOMIS Francefr.loomis.com
Leader in cash management and security services operating the largest value logistics network, offering innovative solutions to accelerate cash flow and availability worldwide |
285 | |||
| 29 |
Apria RSAapriarsa.fr
Apria RSA is a health and insurance management organization with expertise in obligatory health insurance, project management, collective solutions, and customer relations services |
195 | |||
| 30 |
Clinique de l'Estrée - GROUPE ELSANelsan.care
The company is a medical facility offering a wide range of services including surgery, maternity, medicine, dialysis, chemotherapy, and post-care treatments |
153 | |||
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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 11, 2026.
More company lists in the Seine-Saint-Denis department
- The largest companies in the Seine-Saint-Denis department 1,293
- Multinational companies in the Seine-Saint-Denis department 198
- Companies with in-house R&D in the Seine-Saint-Denis department 102
- Retail chains in the Seine-Saint-Denis department 101
- Public sector organisations in the Seine-Saint-Denis department 91
- Distributors and wholesalers in the Seine-Saint-Denis department 81
- IT services companies in the Seine-Saint-Denis department 79
- IT Services and IT Consulting companies in the Seine-Saint-Denis department 78
- Manufacturers in the Seine-Saint-Denis department 72
- Professional services firms in the Seine-Saint-Denis department 71
- Education providers in the Seine-Saint-Denis department 69
- Hardware manufacturers in the Seine-Saint-Denis department 58
- Government Administration companies in the Seine-Saint-Denis department 53
- Family-owned companies in the Seine-Saint-Denis department 50
- Consulting firms in the Seine-Saint-Denis department 44
- Companies with a mobile app in the Seine-Saint-Denis department 44
- Construction companies in the Seine-Saint-Denis department 44
- Logistics companies in the Seine-Saint-Denis department 40
- Professional Training and Coaching companies in the Seine-Saint-Denis department 39
- Advertising Services companies in the Seine-Saint-Denis department 37
- SaaS companies in the Seine-Saint-Denis department 37
- Civic and Social Organizations companies in the Seine-Saint-Denis department 36
- Environmental Services companies in the Seine-Saint-Denis department 36
- Software Development companies in the Seine-Saint-Denis department 35
The same list elsewhere in France
- Critical infrastructure operators in France 2,721
- Critical infrastructure operators in Île-de-France 780
- Critical infrastructure operators in Auvergne-Rhône-Alpes 299
- Critical infrastructure operators in Grand Est 257
- Critical infrastructure operators in Occitanie 216
- Critical infrastructure operators in Nouvelle-Aquitaine 209
- Critical infrastructure operators in Provence-Alpes-Côte d'Azur 200
- Critical infrastructure operators in Hauts-de-France 174
- Critical infrastructure operators in the Hauts-de-Seine department 169
- Critical infrastructure operators in Pays de la Loire 127
- Critical infrastructure operators in Brittany 120
- Critical infrastructure operators in Normandy 103
- Critical infrastructure operators in the Bouches-du-Rhône department 98
- Critical infrastructure operators in the Rhône department 94
- Critical infrastructure operators in Centre-Val de Loire 87
- Critical infrastructure operators in the Nord department 87
- Critical infrastructure operators in Bourgogne-Franche-Comté 76
- Critical infrastructure operators in the Haute-Garonne department 64
- Critical infrastructure operators in the Gironde department 63
- Critical infrastructure operators in the Loire-Atlantique department 59
- Critical infrastructure operators in the Hérault department 57
- Critical infrastructure operators in the Seine-Maritime department 46
- Critical infrastructure operators in the Ille-et-Vilaine department 45
- Critical infrastructure operators in Paris 331