# Top 30 public sector organisations in the Loire-Atlantique department

Tamtam tracks 80 public sector organisations headquartered in the Loire-Atlantique department. This list ranks the 30 largest by number of employees on LinkedIn, led by CHU de Nantes, Nantes Université and Nantes Métropole. Their median headcount is 326. Half of them were founded in 1969 or later. The most common headquarters are Nantes (21) and Saint-Nazaire (2).

This selection of public sector organizations in Loire-Atlantique primarily features large institutions in healthcare, higher education, and government administration. Among them, CHU de Nantes is a major hospital group involved in research and international collaborations, Nantes Université focuses on higher education and innovation, and Nantes Métropole works on local development. Other notable entities include Semitan, managing urban transit in Nantes, and Centrale Nantes, an engineering school.

A clear pattern is the concentration of these significant public bodies within Nantes, which serves as the administrative and educational hub for the region. The organizations range from long-established institutions like CHU de Nantes (founded 1503) and Nantes Université (founded 1460) to more recently established entities like Nantes Métropole (founded 2004), indicating a mix of historical presence and modern administrative structures.

🇫🇷 Loire-Atlantique · 30 companies · Updated Nov 12, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [CHU de Nantes](https://www.tamtam.ai/c/chu-de-nantes) (chu-nantes.fr)<br>The company specializes in technical collaborations, continuing education, scientific research, and assistance for foreign patients in the field of international affairs | Hospitals and Health Care | 🇫🇷 Nantes | 5,305 | 1503 |
| 2 | [Nantes Université](https://www.tamtam.ai/c/nantes-universite) (univ-nantes.fr)<br>Unites higher education, research, and innovation stakeholders to develop research excellence, especially for future health and industry, offering new training opportunities. | Higher Education | 🇫🇷 Nantes | 4,270 | 1460 |
| 3 | [Nantes Métropole](https://www.tamtam.ai/c/nantes-metropole) (linktr.ee)<br>This organization in Nantes and its metropolitan area aims to create a new development model, embracing solidarity, collaboration, creativity, and openness They provide updates on local news | Government Administration | 🇫🇷 Nantes | 2,524 | 2004 |
| 4 | [Région Pays de la Loire](https://www.tamtam.ai/c/region-pays-de-la-loire) (paysdelaloire.fr)<br>Regional government managing economic growth, cultural events, education, transport, innovation, and community services across diverse urban and rural areas. | Government Administration | 🇫🇷 Nantes | 1,457 |  |
| 5 | [Département de Loire-Atlantique](https://www.tamtam.ai/c/departement-de-loire-atlantique) (loire-atlantique.fr)<br>Provides local government administration and public services for the Loire-Atlantique region, managing community needs and regional development. | Government Administration | 🇫🇷 Nantes | 1,437 |  |
| 6 | [Semitan](https://www.tamtam.ai/c/semitan) (semitan.fr)<br>A public-private entity managing public transport in Nantes, overseeing network construction, renovation, and coordination of all mobility services in the region | Urban Transit Services | 🇫🇷 Nantes | 727 | 1979 |
| 7 | [Centre Hospitalier de Saint-Nazaire](https://www.tamtam.ai/c/centre-hospitalier-de-saint-nazaire) (hopital-saintnazaire.fr)<br>Public hospital providing extensive medical, surgical, emergency, mental health, elderly care, and preventive services across multiple regional sites. | Hospitals and Health Care | 🇫🇷 Saint-Nazaire | 669 | 1730 |
| 8 | [Centrale Nantes](https://www.tamtam.ai/c/centrale-nantes) (ec-nantes.fr)<br>Trains versatile engineers with high scientific, technical levels and strong managerial culture, integrating environmental, societal issues into global contexts. | Higher Education | 🇫🇷 Nantes | 600 | 1919 |
| 9 | [Oniris Nantes](https://www.tamtam.ai/c/oniris-nantes) (oniris-nantes.fr)<br>Educates veterinarians, superior technicians, and engineers in animal health, public health, food sciences, and bioprocesses, actively supporting 'one medicine, one health'. | Higher Education | 🇫🇷 Nantes | 543 | 2010 |
| 10 | [Carsat Pays de la Loire](https://www.tamtam.ai/c/carsat-pays-de-la-loire) (carsat-pl.fr)<br>Regional social security organization managing retirement, social action, and occupational risk prevention for employees, retirees, and businesses in Pays de la Loire. | Government Administration | 🇫🇷 Nantes | 491 |  |
| 11 | [Réseau GRETA-CFA des Pays de la Loire](https://www.tamtam.ai/c/reseau-greta-cfa-des-pays-de-la-loire) (greta-cfa-paysdelaloire.fr)<br>Group of public educational institutions pooling resources to offer adult continuing education tailored to local economic needs and equipment. | Professional Training and Coaching | 🇫🇷 Nantes | 394 |  |
| 12 | [CMA Pays de la Loire](https://www.tamtam.ai/c/cma-pays-de-la-loire) (artisanatpaysdelaloire.fr)<br>Represents, defends, and advises 92,360 establishments, supporting economic and social development, with a focus on training future craftspeople. | Government Administration | 🇫🇷 Sainte-Luce-Sur-Loire | 357 | 2015 |
| 13 | [Urssaf Pays de la Loire](https://www.tamtam.ai/c/urssaf-pays-de-la-loire) (urssaf.fr)<br>A company specializing in collecting social security contributions and family allowances on behalf of the government | Government Administration | 🇫🇷 Nantes | 342 |  |
| 14 | [Assurance Maladie de Loire-Atlantique (CPAM)](https://www.tamtam.ai/c/assurance-maladie-de-loire-atlantique-cpam) (cpam44.fr)<br>The company supports over 1 million individuals with healthcare expenses, wellbeing preservation, care coordination, and enhanced protection in difficult situations | Government Administration | 🇫🇷 Nantes | 332 |  |
| 15 | [Faculté de Droit et des Sciences Politiques de Nantes Université](https://www.tamtam.ai/c/faculte-de-droit-et-des-sciences-politiques-de-nantes-universite) (droit.univ-nantes.fr)<br>A leading component of Nantes University offering diverse legal and political science programs, research collaborations, international openness, and competent staff attracting growing student enrollment | Education Administration Programs | 🇫🇷 Nantes | 326 | 1967 |
| 16 | [IUT de Nantes](https://www.tamtam.ai/c/iut-de-nantes) (iutnantes.univ-nantes.fr)<br>Higher education institution offering multidisciplinary technological degrees from Bac+3 to Bac+5 with strong industry ties and research focus. | Higher Education | 🇫🇷 Carquefou | 294 | 1967 |
| 17 | [Ville de Saint-Herblain](https://www.tamtam.ai/c/ville-de-saint-herblain) (saint-herblain.fr)<br>The company is located in Saint-Herblain, the second largest city in Nantes, with a population of 50,000 residents It is conveniently situated near major transportation hubs | Government Administration | 🇫🇷 Saint-Herblain | 283 |  |
| 18 | [Nantes Métropole Habitat](https://www.tamtam.ai/c/nantes-metropole-habitat) (nmh.fr)<br>Public social housing organization managing diverse properties, providing homes for 50,000 tenants, supporting urban development and community engagement. | Real Estate | 🇫🇷 Nantes | 281 | 1913 |
| 19 | [IUT Saint-Nazaire](https://www.tamtam.ai/c/iut-saint-nazaire) (iutsn.fr)<br>Specializing in sustainability training to prepare individuals for a sustainable future | Higher Education | 🇫🇷 Saint-Nazaire | 273 | 1969 |
| 20 | [ensa Nantes](https://www.tamtam.ai/c/ensa-nantes) (nantes.archi.fr)<br>A public institution offering architectural education and research, preparing students for the architect diploma, with international partnerships and a strategic alliance with two other schools | Higher Education | 🇫🇷 Nantes | 249 | 1969 |
| 21 | [Le Voyage à Nantes](https://www.tamtam.ai/c/le-voyage-a-nantes) (levoyageanantes.fr)<br>management of cultural sites and tourism policy implementation in Nantes Métropole, promoting art, culture, and local development projects. | Travel Arrangements | 🇫🇷 Nantes | 224 | 2011 |
| 22 | [IEMN-IAE](https://www.tamtam.ai/c/iemn-iae) (iae.univ-nantes.fr)<br>A leading institution in Nantes offering education in economics, finance, management, and professional development through internships, projects, and international experiences | Higher Education | 🇫🇷 Nantes | 221 | 1958 |
| 23 | [EPSYLAN](https://www.tamtam.ai/c/epsylan) (ch-epsylan.fr)<br>Provider of psychiatric care for all ages in northern Loire-Atlantique, managing various outpatient and inpatient facilities, offering diverse specialized treatments and therapeutic services | Hospitals and Health Care | 🇫🇷 Blain | 198 | 1960 |
| 24 | [Nantes Congress Center](https://www.tamtam.ai/c/nantes-congress-center) (lacite-nantes.fr)<br>A public company in Nantes hosting over 300 events annually, offering diverse event spaces for national and international gatherings of 200 to 4000 participants | Events Services | 🇫🇷 Nantes | 194 | 1991 |
| 25 | [Samoa](https://www.tamtam.ai/c/samoa) (samoa-nantes.fr)<br>The company oversees urban development and economic growth on Nantes island, operating within the Nantes Saint-Nazaire metropolitan area, focusing on creative industries | Architecture and Planning | 🇫🇷 Nantes | 193 | 2003 |
| 26 | [CapAtlantique La Baule-Guérande Agglo](https://www.tamtam.ai/c/capatlantique-la-baule-guerande-agglo) (cap-atlantique.fr)<br>A local government organization managing 15 communes with 75,000 residents, focusing on preserving natural resources and serving the community in Loire-Atlantique and Morbihan | Government Administration | 🇫🇷 La Baule-Escoublac | 175 |  |
| 27 | [Direction régionale de l'environnement, de l'aménagement et du logement des Pays de la Loire](https://www.tamtam.ai/c/direction-regionale-de-l-environnement-de-l-amenagement-et-du-logement-des-pays) (pays-de-la-loire.developpement-durable.gouv.fr)<br>Regional authority for environmental, planning, and housing in the Pays de la Loire region, overseeing policies and projects for sustainable development | Government Administration | 🇫🇷 Nantes | 172 | 2009 |
| 28 | [CA PORNIC AGGLO PAYS DE RETZ](https://www.tamtam.ai/c/ca-pornic-agglo-pays-de-retz) (pornicagglo.fr)<br>Intercommunal structure uniting 15 municipalities in the Pays de Retz area for coordinated regional development and services. | Government Administration | 🇫🇷 Pornic | 159 | 2017 |
| 29 | [Nantes-Saint Nazaire Port](https://www.tamtam.ai/c/nantes-saint-nazaire-port) (port.fr)<br>Public enterprise corporation managing port operations, linking land and sea, providing logistical platform, and contributing to regional economic development and employment. | Maritime Transportation | 🇫🇷 Nantes | 158 | 1966 |
| 30 | [Centre d’Incendie et de Secours](https://www.tamtam.ai/c/centre-d-incendie-et-de-secours) (terre.defense.gouv.fr)<br>A higher education institution located in Indre, France that focuses on fire and rescue services training and education | Higher Education | 🇫🇷 Indre | 154 |  |

## 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.

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- [Construction companies in the Loire-Atlantique department](https://www.tamtam.ai/l/construction-companies-loire-atlantique) (57)

## The same list elsewhere in France

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- [Public sector organisations in Pays de la Loire](https://www.tamtam.ai/l/public-sector-organisations-pays-de-la-loire) (185)
- [Public sector organisations in the Bouches-du-Rhône department](https://www.tamtam.ai/l/public-sector-organisations-bouches-du-rhone) (183)
- [Public sector organisations in Normandy](https://www.tamtam.ai/l/public-sector-organisations-normandy) (166)
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- [Public sector organisations in the Seine-Saint-Denis department](https://www.tamtam.ai/l/public-sector-organisations-seine-saint-denis) (91)
- [Public sector organisations in the Isère department](https://www.tamtam.ai/l/public-sector-organisations-isere) (80)
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- [Public sector organisations in Marseille](https://www.tamtam.ai/l/public-sector-organisations-marseille) (103)
- [Public sector organisations in Toulouse](https://www.tamtam.ai/l/public-sector-organisations-toulouse) (83)

## The same list elsewhere

- [Public sector organisations in the world](https://www.tamtam.ai/l/public-sector-organisations-in-the-world) (18,493)
- [Public sector organisations in Europe](https://www.tamtam.ai/l/public-sector-organisations-in-europe) (8,568)

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Source: https://www.tamtam.ai/l/public-sector-organisations-loire-atlantique