# List of critical infrastructure operators in the Seine-et-Marne department

Tamtam tracks 33 critical infrastructure operators headquartered in the Seine-et-Marne department. This list ranks the 30 largest by number of employees on LinkedIn, led by TSO, Grand Hôpital de l'Est Francilien and SDIS 77 - Sapeurs-pompiers de Seine-et-Marne. Their median headcount is 100. Half of them were founded in 1998 or later. The most common headquarters are Chelles (5), Melun (4) and Champs-sur-Marne (3).

These are critical infrastructure operators in the Seine-et-Marne department, mostly mid-sized firms. The companies listed include TSO, specializing in rail construction and maintenance, and Grand Hôpital de l'Est Francilien, an integrated hospital network. SDIS 77 - Sapeurs-pompiers de Seine-et-Marne focuses on fire prevention and emergency response, while CASDEN Banque Populaire is a cooperative bank for the public sector. CELESTE provides internet and connectivity solutions for businesses.

A clear pattern emerges with a strong presence of companies in the rail transportation sector, such as TSO, TSO CATENAIRES, and FVF - Sécurité Ferroviaire, all headquartered in Chelles. This indicates a significant concentration of expertise and operations related to railway infrastructure in that specific city.

🇫🇷 Seine-et-Marne · 30 companies · Updated Nov 11, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [TSO](https://www.tamtam.ai/c/tso-chelles) (tso.fr)<br>Specializing in rail construction, maintenance, electrification, software development, safety, and rolling stock services, the company offers comprehensive solutions for complex projects | Rail Transportation | 🇫🇷 Chelles | 2,494 | 1927 |
| 2 | [Grand Hôpital de l'Est Francilien](https://www.tamtam.ai/c/grand-hopital-de-l-est-francilien) (ghef.fr)<br>Integrated hospital network providing extensive medical and psychiatric care across multiple sites, serving the northern Seine-et-Marne population. | Government Administration | 🇫🇷 Meaux | 904 | 2017 |
| 3 | [SDIS 77 - Sapeurs-pompiers de Seine-et-Marne](https://www.tamtam.ai/c/sdis-77-sapeurs-pompiers-de-seine-et-marne) (sdis77.fr)<br>A public establishment in Seine-et-Marne focused on preventing, protecting, and fighting fires, as well as providing emergency response in the region | Public Safety | 🇫🇷 Melun | 862 | 1934 |
| 4 | [CASDEN Banque Populaire](https://www.tamtam.ai/c/casden-banque-populaire) (casden.fr)<br>The company is a cooperative bank serving the public sector, offering savings, loans, and insurance with a focus on social values and partnerships | Banking | 🇫🇷 Champs-sur-Marne | 642 | 1951 |
| 5 | [CELESTE](https://www.tamtam.ai/c/celeste-champs-sur-marne) (celeste.fr)<br>A national provider of internet access and connectivity solutions for businesses, offering innovative, high-availability, and eco-friendly services such as fiber optic connections and cloud hosting | Telecommunications | 🇫🇷 Champs-sur-Marne | 537 | 2001 |
| 6 | [TSO CATENAIRES](https://www.tamtam.ai/c/tso-catenaires) (tso.fr)<br>Specializes in designing, installing, and maintaining electrification and power supply systems essential for sustainable railway infrastructure projects worldwide. | Rail Transportation | 🇫🇷 Chelles | 403 |  |
| 7 | [Numericable](https://www.tamtam.ai/c/numericable) (numericable.fr)<br>Leading French cable operator offering modular TV, internet, phone, and mobile services to 98 million households, with extensive coverage and high-speed fiber options | Telecommunications | 🇫🇷 Champs-sur-Marne | 354 | 2007 |
| 8 | [Centre hospitalier du Sud Seine-et-Marne](https://www.tamtam.ai/c/centre-hospitalier-du-sud-seine-et-marne) (ch-sud-seine-et-marne.fr)<br>Groups hospitals in Fontainebleau, Montereau-Fault-Yonne, and Nemours, resulting from a shared medical project to provide healthcare services in the region. | Hospitals and Health Care | 🇫🇷 Fontainebleau | 332 | 2017 |
| 9 | [Fondation Ellen Poidatz](https://www.tamtam.ai/c/fondation-ellen-poidatz) (fondationpoidatz.com)<br>Management of pediatric rehabilitation centers, support for disabled children and adults, adapted schooling, and research in healthcare innovation. | Hospitals and Health Care | 🇫🇷 Chailly-en-Bière | 329 | 1919 |
| 10 | [HOPITAL FORCILLES - Fondation Cognacq-Jay](https://www.tamtam.ai/c/hopital-forcilles-fondation-cognacq-jay) (hopital-forcilles.cognacq-jay.fr)<br>The company provides rehabilitation for patients with chronic diseases, cancer treatment expertise, and medical consultations for locals in Seine-et-Marne | Hospitals and Health Care | 🇫🇷 Férolles-Attilly | 278 | 1964 |
| 11 | [Groupe Hospitalier Sud Ile-de-France](https://www.tamtam.ai/c/groupe-hospitalier-sud-ile-de-france) (ghsif.fr)<br>Leading public healthcare group in Southern Seine-et-Marne, France, comprised of hospitals, health facilities, and a shared direction with a gerontology establishment | Medical Practices | 🇫🇷 Melun | 259 |  |
| 12 | [SIAM](https://www.tamtam.ai/c/siam) (siam77.fr)<br>The Intercommunal Sanitation Syndicate of Marne-la-Vallée collects, transports, and treats wastewater, focusing on energy production and circular economy initiatives for environmental transition | Government Relations Services | 🇫🇷 Saint-Thibault-des-Vignes | 163 | 1974 |
| 13 | [FVF - Sécurité Ferroviaire](https://www.tamtam.ai/c/fvf-securite-ferroviaire) (tso.fr)<br>Since 2012, a company specializing in railway security works on maintenance, regeneration, and new line projects with a focus on safety for clients like SNCF | Rail Transportation | 🇫🇷 Chelles | 148 |  |
| 14 | [TSO SIGNALISATION](https://www.tamtam.ai/c/tso-signalisation) (tso.fr)<br>The company offers a comprehensive range of railway signaling services including technical studies, civil engineering, signaling, telecommunications, rockfall detection, and railway safety | Rail Transportation | 🇫🇷 Chelles | 105 |  |
| 15 | [ProCars](https://www.tamtam.ai/c/procars) (procars.com)<br>ProCars is a private and independent road passenger transport company in Île-de-France, offering various services including tourist transportation and event services | Sightseeing Transportation | 🇫🇷 Provins | 100 | 1950 |
| 16 | [Clinique Saint-Jean l'Ermitage](https://www.tamtam.ai/c/clinique-saint-jean-l-ermitage) (clinique-saint-jean-ermitage.fr)<br>A leading private clinic in Île-de-France with over 50 years of experience, offering specialized medical care in surgery, medicine, rehabilitation, imaging, and oncology | Hospitals and Health Care | 🇫🇷 Melun | 95 | 1957 |
| 17 | [CH Léon Binet - Provins](https://www.tamtam.ai/c/ch-leon-binet-provins)<br>Diagnostic, treatment, prevention, and health education services, operating a hospital with 399 beds and 60 places, employing 900 professionals. | Hospitals and Health Care | 🇫🇷 Provins | 67 | 1974 |
| 18 | [HOPITAL PRIVE DE MARNE CHANTEREINE](https://www.tamtam.ai/c/hopital-prive-de-marne-chantereine) (hopital-prive-marne-chantereine.ramsaysante.fr)<br>A medical practice company located in Île-de-France, France, providing healthcare services at RUE MARIE CURIE in Brou Sur Chantereine | Hospitals and Health Care | 🇫🇷 Brou-sur-Chantereine | 65 | 1968 |
| 19 | [Appliwave](https://www.tamtam.ai/c/appliwave) (appliwave.com)<br>An operator Cloud and Telecom provider through a network of partners, offering innovative solutions for SMEs and midsize companies in France and Germany | Computer Networking Products | 🇫🇷 Croissy-Beaubourg | 40 | 2010 |
| 20 | [Communauté de Communes Brie des Rivières et Châteaux - CCBRC (77)](https://www.tamtam.ai/c/communaute-de-communes-brie-des-rivieres-et-chateaux-ccbrc-77) (briedesrivieresetchateaux.fr)<br>Rural intercommunal group, 31 municipalities, 39,445 inhabitants. Historical and landscape heritage, castles and rivers. South Seine-et-Marne. | Government Administration | 🇫🇷 Le Châtelet-en-Brie | 39 | 2017 |
| 21 | [MÉDECINE INTENSIVE-RÉANIMATION GHSIF MELUN](https://www.tamtam.ai/c/medecine-intensive-reanimation-ghsif-melun) (ghsif.fr)<br>The company provides intensive care services for critically ill patients, offering advanced diagnostic and treatment techniques for various organ failures | Wellness and Fitness Services | 🇫🇷 Melun | 36 |  |
| 22 | [SIFEL](https://www.tamtam.ai/c/sifel) (tso.fr)<br>Specialized in maintenance, repair, and refurbishment of railway motorized vehicles, particularly locomotives, ensuring proper upkeep of the fleet | Rail Transportation | 🇫🇷 Chelles | 35 |  |
| 23 | [HAD de la région de Melun](https://www.tamtam.ai/c/had-de-la-region-de-melun) (hadmelun.fr)<br>Established in May 2016, the company provides comprehensive healthcare services to patients at home in the Melun region through a non-profit private healthcare partnership | Hospitals and Health Care | 🇫🇷 Vaux-le-Pénil | 34 | 2016 |
| 24 | [CLINIQUE DE MONTEVRAIN](https://www.tamtam.ai/c/clinique-de-montevrain) (clinique-montevrain.ramsaysante.fr)<br>A medical practice company located in Montevrain, France, offering healthcare services at 15 RTE DE PROVINS in Îledefrance | Hospitals and Health Care | 🇫🇷 Montévrain | 30 | 2012 |
| 25 | [PSP GROUPE](https://www.tamtam.ai/c/psp-groupe) (psp-groupe.fr)<br>Specialized in partial and full load transport, express and courier services across France and Europe, including import, export, and logistics. | Truck Transportation | 🇫🇷 Brie-Comte-Robert | 29 | 2007 |
| 26 | [Mainfreight France](https://www.tamtam.ai/c/mainfreight-france) (mainfreight.com)<br>Specialist in palletized groupage and full load transport across France and Europe, including hazardous goods with real-time tracking. | Truck Transportation | 🇫🇷 Mitry-Mory | 25 | 1991 |
| 27 | [SIETREM](https://www.tamtam.ai/c/sietrem) (sietrem.fr)<br>A mixed syndicate managing waste collection, treatment, and valorization for 31 municipalities, also running a waste prevention program, led by Christian ROBACHE | Government Administration | 🇫🇷 Saint-Thibault-des-Vignes | 25 | 1962 |
| 28 | [MEDIA FRET](https://www.tamtam.ai/c/media-fret) (mediafret.com)<br>Specialized transport and logistics services with extensive experience, ensuring secure, cost-effective freight delivery across France and internationally. | Truck Transportation | 🇫🇷 Le Mesnil-Amelot | 22 | 1998 |
| 29 | [Keolis Portes et Val de Brie](https://www.tamtam.ai/c/keolis-portes-et-val-de-brie)<br>A global public transport operator, leading in automatic metro and tramway systems, as well as healthcare transport and parking services Serving 300 authorities worldwide | Ground Passenger Transportation | 🇫🇷 Brie-Comte-Robert | 20 | 2023 |
| 30 | [Keolis Roissy Pays de France Est](https://www.tamtam.ai/c/keolis-roissy-pays-de-france-est) (iledefrance-mobilites.fr)<br>Global public transport operator providing services in 16 countries on 4 continents, specializing in automated metros, trams, medical transport, and parking solutions Serving 3 billion passengers annually | Ground Passenger Transportation | 🇫🇷 Dammartin-en-Goële | 15 | 2023 |

## 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-et-Marne department

- [The largest companies in the Seine-et-Marne department](https://www.tamtam.ai/l/largest-companies-seine-et-marne) (947)
- [Multinational companies in the Seine-et-Marne department](https://www.tamtam.ai/l/multinational-companies-seine-et-marne) (139)
- [Companies with in-house R&D in the Seine-et-Marne department](https://www.tamtam.ai/l/r-and-d-companies-seine-et-marne) (104)
- [Manufacturers in the Seine-et-Marne department](https://www.tamtam.ai/l/manufacturers-seine-et-marne) (100)
- [Hardware manufacturers in the Seine-et-Marne department](https://www.tamtam.ai/l/hardware-companies-seine-et-marne) (84)
- [Distributors and wholesalers in the Seine-et-Marne department](https://www.tamtam.ai/l/distributors-and-wholesalers-seine-et-marne) (82)
- [Retail chains in the Seine-et-Marne department](https://www.tamtam.ai/l/retail-chains-seine-et-marne) (68)
- [Construction companies in the Seine-et-Marne department](https://www.tamtam.ai/l/construction-companies-seine-et-marne) (57)
- [Family-owned companies in the Seine-et-Marne department](https://www.tamtam.ai/l/family-owned-companies-seine-et-marne) (49)
- [Public sector organisations in the Seine-et-Marne department](https://www.tamtam.ai/l/public-sector-organisations-seine-et-marne) (49)
- [Professional services firms in the Seine-et-Marne department](https://www.tamtam.ai/l/professional-services-firms-seine-et-marne) (41)
- [Government Administration companies in the Seine-et-Marne department](https://www.tamtam.ai/l/government-administration-companies-seine-et-marne) (39)
- [Industrial Machinery Manufacturing companies in the Seine-et-Marne department](https://www.tamtam.ai/l/industrial-machinery-manufacturing-companies-seine-et-marne) (34)
- [Wholesale companies in the Seine-et-Marne department](https://www.tamtam.ai/l/wholesale-companies-seine-et-marne) (34)
- [Retail companies in the Seine-et-Marne department](https://www.tamtam.ai/l/retail-companies-seine-et-marne) (33)
- [Education providers in the Seine-et-Marne department](https://www.tamtam.ai/l/education-companies-seine-et-marne) (31)
- [IT Services and IT Consulting companies in the Seine-et-Marne department](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-seine-et-marne) (31)
- [IT services companies in the Seine-et-Marne department](https://www.tamtam.ai/l/it-services-companies-seine-et-marne) (29)
- [Contract manufacturers in the Seine-et-Marne department](https://www.tamtam.ai/l/contract-manufacturers-seine-et-marne) (26)
- [Healthcare providers in the Seine-et-Marne department](https://www.tamtam.ai/l/healthcare-providers-seine-et-marne) (26)
- [Higher Education companies in the Seine-et-Marne department](https://www.tamtam.ai/l/higher-education-companies-seine-et-marne) (25)

## The same list elsewhere in France

- [Critical infrastructure operators in France](https://www.tamtam.ai/l/critical-infrastructure-operators-france) (2,721)
- [Critical infrastructure operators in Île-de-France](https://www.tamtam.ai/l/critical-infrastructure-operators-ile-de-france) (780)
- [Critical infrastructure operators in Auvergne-Rhône-Alpes](https://www.tamtam.ai/l/critical-infrastructure-operators-auvergne-rhone-alpes) (299)
- [Critical infrastructure operators in Grand Est](https://www.tamtam.ai/l/critical-infrastructure-operators-grand-est) (257)
- [Critical infrastructure operators in Occitanie](https://www.tamtam.ai/l/critical-infrastructure-operators-occitanie) (216)
- [Critical infrastructure operators in Nouvelle-Aquitaine](https://www.tamtam.ai/l/critical-infrastructure-operators-nouvelle-aquitaine) (209)
- [Critical infrastructure operators in Provence-Alpes-Côte d'Azur](https://www.tamtam.ai/l/critical-infrastructure-operators-provence-alpes-cote-dazur) (200)
- [Critical infrastructure operators in Hauts-de-France](https://www.tamtam.ai/l/critical-infrastructure-operators-hauts-de-france) (174)
- [Critical infrastructure operators in the Hauts-de-Seine department](https://www.tamtam.ai/l/critical-infrastructure-operators-hauts-de-seine) (169)
- [Critical infrastructure operators in Pays de la Loire](https://www.tamtam.ai/l/critical-infrastructure-operators-pays-de-la-loire) (127)
- [Critical infrastructure operators in Brittany](https://www.tamtam.ai/l/critical-infrastructure-operators-brittany) (120)
- [Critical infrastructure operators in Normandy](https://www.tamtam.ai/l/critical-infrastructure-operators-normandy) (103)
- [Critical infrastructure operators in the Bouches-du-Rhône department](https://www.tamtam.ai/l/critical-infrastructure-operators-bouches-du-rhone) (98)
- [Critical infrastructure operators in the Rhône department](https://www.tamtam.ai/l/critical-infrastructure-operators-rhone) (94)
- [Critical infrastructure operators in Centre-Val de Loire](https://www.tamtam.ai/l/critical-infrastructure-operators-centre-val-de-loire) (87)
- [Critical infrastructure operators in the Nord department](https://www.tamtam.ai/l/critical-infrastructure-operators-nord) (87)
- [Critical infrastructure operators in Bourgogne-Franche-Comté](https://www.tamtam.ai/l/critical-infrastructure-operators-bourgogne-franche-comte) (76)
- [Critical infrastructure operators in the Haute-Garonne department](https://www.tamtam.ai/l/critical-infrastructure-operators-haute-garonne) (64)
- [Critical infrastructure operators in the Gironde department](https://www.tamtam.ai/l/critical-infrastructure-operators-gironde) (63)
- [Critical infrastructure operators in the Loire-Atlantique department](https://www.tamtam.ai/l/critical-infrastructure-operators-loire-atlantique) (59)
- [Critical infrastructure operators in the Hérault department](https://www.tamtam.ai/l/critical-infrastructure-operators-herault) (57)
- [Critical infrastructure operators in the Seine-Saint-Denis department](https://www.tamtam.ai/l/critical-infrastructure-operators-seine-saint-denis) (53)
- [Critical infrastructure operators in the Seine-Maritime department](https://www.tamtam.ai/l/critical-infrastructure-operators-seine-maritime) (46)
- [Critical infrastructure operators in Paris](https://www.tamtam.ai/l/critical-infrastructure-operators-paris) (331)

---

Source: https://www.tamtam.ai/l/critical-infrastructure-operators-seine-et-marne