# Critical infrastructure operators headquartered in the Essonne department Tamtam tracks 32 critical infrastructure operators headquartered in the Essonne department. This list ranks the 30 largest by number of employees on LinkedIn, led by ASN, CENTRE HOSPITALIER SUD FRANCILIEN and French bee. Their median headcount is 98. Half of them were founded in 1996 or later. The most common headquarters are Massy (3), Wissous (2) and Évry-Courcouronnes (2). The companies listed in Essonne are primarily critical infrastructure operators, with a strong emphasis on healthcare. They range from large public health institutions to specialized private hospitals. Notable examples include CENTRE HOSPITALIER SUD FRANCILIEN, a public healthcare provider, and Hôpital privé Jacques Cartier, a private hospital specializing in cardiology. ASN designs and maintains submarine cable systems, while French bee is a long-haul airline. The data shows a significant concentration in the healthcare sector, with many hospitals and clinics providing diverse medical services across the department. Beyond healthcare, there are also key players in telecommunications, such as ASN and Axians Rail, and in waste management, like SEMARDEL. 🇫🇷 Essonne · 30 companies · Updated Nov 11, 2026 | # | Company | Industry | Headquarters | Employees | Founded | |---|---|---|---|---|---| | 1 | [ASN](https://www.tamtam.ai/c/asn) (asn.com)
Designs, installs, and maintains global optical submarine cable systems for telecom, content providers, and offshore oil and gas industries. | Telecommunications | 🇫🇷 Les Ulis | 1,717 | 1994 | | 2 | [CENTRE HOSPITALIER SUD FRANCILIEN](https://www.tamtam.ai/c/centre-hospitalier-sud-francilien) (chsf.fr)
Public healthcare institution serving one million people in southern Île-de-France, providing medical services and hospital care to the community. | Hospitals and Health Care | 🇫🇷 Corbeil-Essonnes | 1,219 | | | 3 | [French bee](https://www.tamtam.ai/c/french-bee) (frenchbee.com)
A French long-haul airline offering affordable flights to various destinations with modern Airbus A350 planes and a focus on reducing carbon footprint | Airlines and Aviation | 🇫🇷 Wissous | 540 | 2016 | | 4 | [Groupe hospitalier Nord-Essonne](https://www.tamtam.ai/c/groupe-hospitalier-nord-essonne) (gh-nord-essonne.fr)
Regional hospital network providing comprehensive medical services including emergency, maternity, pediatrics, surgery, psychiatry, and critical care with modern technical facilities. | Hospitals and Health Care | 🇫🇷 Orsay | 446 | | | 5 | [Centre Hospitalier de Bligny](https://www.tamtam.ai/c/centre-hospitalier-de-bligny) (chbligny.fr)
Non-profit hospital specializing in cardiovascular, respiratory, oncology, hematology, infectious diseases with acute and rehabilitation care services. | Hospitals and Health Care | 🇫🇷 Briis-sous-Forges | 280 | 1901 | | 6 | [Hôpital privé Jacques Cartier](https://www.tamtam.ai/c/hopital-prive-jacques-cartier) (hopital-prive-jacques-cartier-massy.ramsaysante.fr)
Leading private hospital in Southern Paris, offers general and specialized surgery, emergency services, advanced medical imaging, and renowned adult and pediatric cardiology. | Hospitals and Health Care | 🇫🇷 Massy | 252 | 1996 | | 7 | [Cœur d'Essonne Agglomération](https://www.tamtam.ai/c/coeur-d-essonne-agglomeration) (coeuressonne.fr)
Local government collaboration of 21 communes providing quality public services, supporting 203,000 residents and fostering regional development projects. | Government Administration | 🇫🇷 Sainte-Geneviève-des-Bois | 221 | 2016 | | 8 | [Groupe Hospitalier les Cheminots](https://www.tamtam.ai/c/groupe-hospitalier-les-cheminots) (ghc91.fr)
Two healthcare facilities specializing in post-acute care and rehabilitation services, located in Draveil and Ris Orangis, France. | Hospitals and Health Care | 🇫🇷 Draveil | 201 | | | 9 | [HOPITAL PRIVE CLAUDE GALIEN](https://www.tamtam.ai/c/hopital-prive-claude-galien) (hopital-prive-claude-galien-quincy-sous-senart.ramsaysante.fr)
Private hospital group. Advanced medical facility. General and orthopedic surgery, cardiology, hemodialysis. Located 25 km from Paris, 289 beds. | Hospitals and Health Care | 🇫🇷 Quincy-Sous-Sénart | 190 | 1995 | | 10 | [Clinique de L'Yvette](https://www.tamtam.ai/c/clinique-de-l-yvette) (clinique-yvette.com)
Offers surgical, obstetrical care, specialized hand emergency services, cancer treatment, morbid obesity management, and breast cancer screening, including reconstructive surgery. | Hospitals and Health Care | 🇫🇷 Longjumeau | 142 | 1965 | | 11 | [SEMARDEL](https://www.tamtam.ai/c/semardel) (semardel.fr)
Specialized in waste collection, sorting, treatment, and recovery across multiple waste streams including household, industrial, and electronic waste. | Waste Treatment and Disposal | 🇫🇷 Vert-le-Grand | 129 | 1984 | | 12 | [HOPITAL LES MAGNOLIAS](https://www.tamtam.ai/c/hopital-les-magnolias) (lesmagnolias-univi.fr)
A non-profit private healthcare facility in Essonne, near Paris, specializing in geriatric care, promoting healthy aging and autonomy for seniors | Hospitals and Health Care | 🇫🇷 Ballainvilliers | 127 | 1974 | | 13 | [CA CONSUMER FINANCE](https://www.tamtam.ai/c/ca-consumer-finance) (ca-cf.fr)
A financial services company based in France, specializing in consumer finance solutions | Financial Services | 🇫🇷 Massy | 123 | | | 14 | [Centre hospitalier d’Arpajon](https://www.tamtam.ai/c/centre-hospitalier-d-arpajon) (ch-arpajon.fr)
A hospital located in Essonne offering quality healthcare services across six specialized departments and a technical platform, emphasizing professional skills and human qualities | Hospitals and Health Care | 🇫🇷 Arpajon | 104 | | | 15 | [Axians Rail](https://www.tamtam.ai/c/axians-rail) (axians.fr)
Axians Rail, a subsidiary of VINCI Énergies, specializes in telecommunications and signaling infrastructure for railway networks, offering design, construction, and testing services nationwide | Telecommunications | 🇫🇷 Massy | 98 | 2016 | | 16 | [SyAGE](https://www.tamtam.ai/c/syage-montgeron) (syage.org)
A syndicate protecting water resources and biodiversity in the Yerres-Seine watershed through managing wastewater, rainwater, rivers, biodiversity, and water planning | Government Administration | 🇫🇷 Montgeron | 88 | 1952 | | 17 | [ADP Management](https://www.tamtam.ai/c/adp-management) (parisaeroport.fr)
A subsidiary of Aéroports de Paris, specializing in investing and managing airport operations in various international locations, focusing on sustainable development and route development | Aviation and Aerospace Component Manufacturing | 🇫🇷 Wissous | 87 | 1991 | | 18 | [Communauté de communes entre Juine et Renarde](https://www.tamtam.ai/c/communaute-de-communes-entre-juine-et-renarde) (entrejuineetrenarde.org)
An intermunicipal structure in France's Essonne region, uniting 16 towns to develop and manage projects for a population of 27,500 residents | Government Relations Services | 🇫🇷 Étréchy | 74 | 2003 | | 19 | [SEMAER](https://www.tamtam.ai/c/semaer) (semardel.fr)
A subsidiary specializing in waste management services such as waste collection, urban cleaning, equipment rental, and waste facility management | Waste Collection | 🇫🇷 Vert-le-Grand | 68 | | | 20 | [ETMF](https://www.tamtam.ai/c/etmf) (etmftransport.fr)
Specialized in operating maintenance and freight trains across France, providing reliable and safe services to meet clients' needs with a focus on safety and teamwork | Rail Transportation | 🇫🇷 Lisses | 66 | 2012 | | 21 | [Hôpital Privé du Val d'Yerres](https://www.tamtam.ai/c/hopital-prive-du-val-d-yerres) (hopital-prive-val-dyerres.com)
A private hospital in the southeast of Paris with 151 beds, offering surgical services, emergency care, laboratory services, medical imaging, and various medical specialties | Hospitals and Health Care | 🇫🇷 Yerres | 65 | | | 22 | [BANQUE CHABRIERES](https://www.tamtam.ai/c/banque-chabrieres) (banque-chabrieres.fr)
A banking subsidiary of Groupement des Mousquetaires, continuously evolving its services since 1988 to provide optimal banking products to clients | Banking | 🇫🇷 Bondoufle | 58 | 1988 | | 23 | [SIARCE](https://www.tamtam.ai/c/siarce) (siarce.fr)
The company is a mixed syndicate implementing a sustainable development policy focused on water management and environmental protection for its member municipalities | Government Administration | 🇫🇷 Corbeil-Essonnes | 48 | 1958 | | 24 | [Clinique Pasteur - Almaviva Santé](https://www.tamtam.ai/c/clinique-pasteur-almaviva-sante) (clinique-pasteur-risorangis.fr)
Specializes in adult cancer care, offering chemotherapy treatments and multidisciplinary support to improve patient autonomy and facilitate their return home. | Hospitals and Health Care | 🇫🇷 Ris-Orangis | 38 | | | 25 | [KEOLIS VAL D'YERRES VAL DE SEINE](https://www.tamtam.ai/c/keolis-val-d-yerres-val-de-seine) (keolis-idf.com)
The company operates and maintains urban, suburban, and interurban transport networks for over 300 authorities in 13 countries, offering a variety of transport modes | Urban Transit Services | 🇫🇷 Draveil | 20 | 2022 | | 26 | [CLINIQUE DE L YVETTE](https://www.tamtam.ai/c/clinique-de-l-yvette-longjumeau) (clinique-yvette.com)
Healthcare facility in Longjumeau with 143 beds, three entrances, medical imaging, emergency services, and a 200-space parking lot. | Hospitals and Health Care | 🇫🇷 Longjumeau | 18 | | | 27 | [Interlink Transport SAS](https://www.tamtam.ai/c/interlink-transport-sas)
Fleet of vehicles from light to 44t trailers, providing complete transport and logistics solutions for industrial B2B mass flows. | Transportation, Logistics, Supply Chain and Storage | 🇫🇷 Évry-Courcouronnes | 17 | 2012 | | 28 | [SYNDICAT DES EAUX OUEST ESSONNE](https://www.tamtam.ai/c/syndicat-des-eaux-ouest-essonne) (eauouestessonne.fr)
This company is involved in water management services in the western Essonne region, ensuring access to safe and clean water for residents | Utilities | 🇫🇷 Forges-les-Bains | 12 | | | 29 | [L'Aveyronnaise d'Assurances](https://www.tamtam.ai/c/l-aveyronnaise-d-assurances) (laveyronnaisedassurances.fr)
The company provides health, automobile, and home insurance policies to individuals and families to protect their well-being and assets | Insurance | 🇫🇷 Longjumeau | 5 | 2018 | | 30 | [SPL - Confluence Seine Essonne Energie](https://www.tamtam.ai/c/spl-confluence-seine-essonne-energie)
A Public Local Company converts wastewater residues into energy resources, a pioneering initiative in Essonne, France | Renewable Energy Power Generation | 🇫🇷 Évry-Courcouronnes | 4 | 2021 | ## 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 Essonne department - [The largest companies in the Essonne department](https://www.tamtam.ai/l/largest-companies-essonne) (1,149) - [Companies with in-house R&D in the Essonne department](https://www.tamtam.ai/l/r-and-d-companies-essonne) (198) - [Multinational companies in the Essonne department](https://www.tamtam.ai/l/multinational-companies-essonne) (156) - [Manufacturers in the Essonne department](https://www.tamtam.ai/l/manufacturers-essonne) (127) - [Hardware manufacturers in the Essonne department](https://www.tamtam.ai/l/hardware-companies-essonne) (114) - [Distributors and wholesalers in the Essonne department](https://www.tamtam.ai/l/distributors-and-wholesalers-essonne) (76) - [IT Services and IT Consulting companies in the Essonne department](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-essonne) (70) - [Professional services firms in the Essonne department](https://www.tamtam.ai/l/professional-services-firms-essonne) (68) - [Public sector organisations in the Essonne department](https://www.tamtam.ai/l/public-sector-organisations-essonne) (66) - [Aerospace and defence companies in the Essonne department](https://www.tamtam.ai/l/aerospace-and-defense-companies-essonne) (65) - [IT services companies in the Essonne department](https://www.tamtam.ai/l/it-services-companies-essonne) (60) - [Retail chains in the Essonne department](https://www.tamtam.ai/l/retail-chains-essonne) (59) - [Construction companies in the Essonne department](https://www.tamtam.ai/l/construction-companies-essonne) (56) - [Software Development companies in the Essonne department](https://www.tamtam.ai/l/software-development-companies-essonne) (51) - [Pharmaceutical companies in the Essonne department](https://www.tamtam.ai/l/pharmaceutical-companies-essonne) (45) - [Electronics and semiconductor companies in the Essonne department](https://www.tamtam.ai/l/electronics-companies-essonne) (44) - [Research institutes in the Essonne department](https://www.tamtam.ai/l/research-institutes-essonne) (42) - [Events Services companies in the Essonne department](https://www.tamtam.ai/l/events-services-companies-essonne) (41) - [SaaS companies in the Essonne department](https://www.tamtam.ai/l/saas-companies-essonne) (41) - [Consulting firms in the Essonne department](https://www.tamtam.ai/l/consulting-firms-essonne) (40) - [Family-owned companies in the Essonne department](https://www.tamtam.ai/l/family-owned-companies-essonne) (38) - [Contract manufacturers in the Essonne department](https://www.tamtam.ai/l/contract-manufacturers-essonne) (35) - [Research Services companies in the Essonne department](https://www.tamtam.ai/l/research-services-companies-essonne) (35) - [Education providers in the Essonne department](https://www.tamtam.ai/l/education-companies-essonne) (30) ## 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-essonne