The Essonne department hosts a concentration of companies primarily focused on aerospace and defense, alongside general engineering and industrial manufacturing. These firms range from established research institutions and mid-sized manufacturers to younger companies specializing in niche technologies. Notable examples include ONERA, which conducts aerospace and defense research; TechnicAtome, a specialist in compact nuclear reactor design; and Exotrail, which develops propulsion systems for space mobility. The presence of companies like UMS, manufacturing RF and millimeter-wave integrated circuits, and Sofradir, designing infrared technologies, highlights a strong specialization in advanced electronics and components.
A clear pattern among these companies is their deep involvement in high-technology manufacturing and engineering services, particularly for demanding sectors. Many of them are based in cities like Palaiseau, Les Ulis, and Massy, forming a cluster of expertise in the region. The founding dates vary, indicating a mix of long-standing players and more recent ventures, all contributing to the aerospace and defense supply chain.
| # | Company | Employees | |||
|---|---|---|---|---|---|
| 1 |
ONERA - The French Aerospace Labonera.fr
Researching future aerospace and defense challenges, contributing to industry competitiveness through expertise in all related disciplines and technologies. |
2,097 | |||
| 2 |
TechnicAtometechnicatome.com
Specialized in compact nuclear reactor design, construction, and maintenance for various sectors including naval propulsion, research, medicine, and energy |
1,467 | |||
| 3 |
Vernet Groupvernet-group.com
Family company, world leader in thermal regulation, designing and manufacturing thermostats and thermostatic elements for automotive, heating, and plumbing industries. |
418 | |||
| 4 | 244 | ||||
| 5 |
Exotrailexotrail.com
Develops and operates propulsion systems, mission simulation software, and orbital transfer vehicles for efficient, sustainable space mobility, enabling telecommunication, Earth observation, space exploration. |
215 | |||
| 6 |
UMS - United Monolithic Semiconductorsums-rf.com
Designs and manufactures GaAs and GaN based RF and millimeter-wave integrated circuits and provides advanced foundry services for critical applications. |
210 | |||
| 7 |
Archosarchos.com
A pioneering consumer electronics company based in France, known for innovation in mobile solutions, AI, blockchains, and IoT networks |
170 | |||
| 8 |
Composite Industrie S.A.composite-industrie.com
Specializes in manufacturing and repairing composite and hybrid metal-composite parts for aerospace, military, telecom, and transportation industries worldwide. |
128 | |||
| 9 |
Supratecsupratec.fr
Development of integrated automation technologies and services to optimize manufacturing processes in preparation, handling, assembly, and product control sectors. |
125 | |||
| 10 |
Sofradirlynred.com
Designs and manufactures high-quality infrared technologies for aerospace, defense, and commercial markets, including infrared detectors for military programs and commercial thermal imaging equipment. |
123 | |||
| 11 |
Exens Groupexens-solutions.com
Specializing in RF and microwave electronics, this company designs and manufactures components, modules, and subsystems for various industries on a global scale |
87 | |||
| 12 |
Senior Aerospace Calorstatsenior-calorstat.com
Manufactures build-to-spec assemblies and bellows systems for aerospace, nuclear, semiconductor, and other high-tech industries, ensuring optimum performance in demanding environments. |
86 | |||
| 13 |
Mach Aero - Groupe MinebeaMitsumimachaero.com
specialized manufacturing of spherical joint mechanical components compensating alignment variations in aircraft equipment, with operations in France and India. |
73 | |||
| 14 |
STAE (France)stae.fr
The company specializes in supporting clients in the design, industrialization, and production of highly technical technological products in various sectors |
62 | |||
| 15 |
ThrustMethrustme.fr
Provides high-performing in-orbit mobility solutions, offering disruptive, integrated, and smart space propulsion systems for satellite constellations, including an iodine-fueled electric propulsion system. |
62 | |||
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 |
NUCLETUDESnucletudes.ariane.group
Specialized in engineering and testing for protection against severe radiative and electromagnetic aggressions, as a subsidiary of a global aerospace company |
61 | |||
| 17 |
Mecalectromecalectro.com
Design and manufacture of custom electromagnetic actuators, locks, and safety latches for aerospace, defense, medical, and other sectors. |
56 | |||
| 18 |
SERMserm-meca.com
Specialized in high precision metal and plastics machining, SERM offers turnkey solutions for industries like aerospace, nuclear, and medical, with quality certified by EN 9100 and ISO 9001 |
56 | |||
| 19 |
PROTECTICprotectic.fr
Engineering company, intervening in large-scale industrial projects (aeronautics, space, defense, energy, transport). Accompanying major industrial players in product development. |
50 | |||
| 20 |
GACI Technologiesgaci.fr
Wholesale company operating from Villebon sur Yvette, France, specializing in distribution and supply of various products to retailers. |
48 | |||
| 21 |
BERNIER Connectbernier.tm.fr
Specializing in designing and manufacturing connectors tailored for challenging environments, ensuring reliable connectivity in harsh conditions |
44 | |||
| 22 | 41 | ||||
| 23 |
SEDI-ATI by Fiber Optics Groupsedi-ati.com
Design and manufacture optical fiber solutions for extreme environments, including high temperature, pressure, radiation, and specialized industrial and medical applications. |
41 | |||
| 24 |
Hologardehologarde.com
Unique global integrated solution for drone detection, threat neutralization, and collaborative drone management for enhanced security. |
41 | |||
| 25 |
mirSensemirsense.com
A French high tech company specializing in QCL-based solutions for defense, security, industry/environment markets, offering DFB, high-power lasers, and OEM gas analyzers |
36 | |||
| 26 |
SpaceDreamSspacedreams.com
Provides turnkey ground segment solutions, operational maintenance, launch services, and digital twins using modular, interoperable systems to reduce costs for European spaceports. |
36 | |||
| 27 |
CS³ - Centre Spatial de CentraleSupélec pour les CubeSatsfacebook.com
A student space center focused on developing CubeSat platforms for educational and research purposes |
32 | |||
| 28 |
HyLighthylight.aero
HyLight develops drones for eco-friendly inspections of gas infrastructure and power lines to prevent environmental harm, aiming to revolutionize aerial data collection |
31 | |||
| 29 |
Noxant, an Exosens companynoxant.com
Experts in optronic systems, designs and develops revolutionary vision solutions for industrial and surveillance applications. Innovative vision technology for high-performance systems. |
29 | |||
| 30 | 28 | ||||
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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 Essonne department
- The largest companies in the Essonne department 1,149
- Companies with in-house R&D in the Essonne department 198
- Multinational companies in the Essonne department 156
- Manufacturers in the Essonne department 127
- Hardware manufacturers in the Essonne department 114
- Distributors and wholesalers in the Essonne department 76
- IT Services and IT Consulting companies in the Essonne department 70
- Professional services firms in the Essonne department 68
- Public sector organisations in the Essonne department 66
- IT services companies in the Essonne department 60
- Retail chains in the Essonne department 59
- Construction companies in the Essonne department 56
- Software Development companies in the Essonne department 51
- Pharmaceutical companies in the Essonne department 45
- Electronics and semiconductor companies in the Essonne department 44
- Research institutes in the Essonne department 42
- Events Services companies in the Essonne department 41
- SaaS companies in the Essonne department 41
- Consulting firms in the Essonne department 40
- Family-owned companies in the Essonne department 38
- Contract manufacturers in the Essonne department 35
- Research Services companies in the Essonne department 35
- Critical infrastructure operators in the Essonne department 32
- Education providers in the Essonne department 30
The same list elsewhere in France
- Aerospace and defence companies in France 1,572
- Aerospace and defence companies in Île-de-France 409
- Aerospace and defence companies in Occitanie 278
- Aerospace and defence companies in Auvergne-Rhône-Alpes 200
- Aerospace and defence companies in the Haute-Garonne department 186
- Aerospace and defence companies in Nouvelle-Aquitaine 136
- Aerospace and defence companies in Provence-Alpes-Côte d'Azur 116
- Aerospace and defence companies in Grand Est 97
- Aerospace and defence companies in the Yvelines department 65
- Aerospace and defence companies in Brittany 63
- Aerospace and defence companies in Pays de la Loire 63
- Aerospace and defence companies in the Bouches-du-Rhône department 61
- Aerospace and defence companies in the Hauts-de-Seine department 56
- Aerospace and defence companies in Centre-Val de Loire 53
- Aerospace and defence companies in the Gironde department 51
- Aerospace and defence companies in Bourgogne-Franche-Comté 50
- Aerospace and defence companies in Hauts-de-France 40
- Aerospace and defence companies in the Rhône department 37
- Aerospace and defence companies in Normandy 36
- Aerospace and defence companies in the Haute-Savoie department 35
- Aerospace and defence companies in the Val-d'Oise department 31
- Aerospace and defence companies in the Var department 30
- Aerospace and defence companies in Paris 117
- Aerospace and defence companies in Toulouse 94