# List of cybersecurity companies in the Yvelines department
Tamtam tracks 25 cybersecurity companies headquartered in the Yvelines department. This list ranks all of them by number of employees on LinkedIn, led by Saphir Group, Airbus Defence and Space Cyber and act digital EMEA - Alter Solutions. Their median headcount is 38. Half of them were founded in 2005 or later. The most common headquarters are Velizy-Villacoublay (6), Versailles (4) and Chatou (3).
The Yvelines department hosts a concentration of IT services and IT consulting firms, many of which specialize in cybersecurity. These companies range from established mid-sized firms to younger enterprises. Noteworthy examples include Saphir Group, which provides Industry 4.0 solutions and OT security, and Airbus Defence and Space Cyber, known for its cybersecurity solutions for defense and governmental clients. ERCOM offers cutting-edge cybersecurity and communication network solutions, while M茅diane Syst猫me specializes in secure real-time operating systems and industrial network solutions.
A significant portion of these companies are headquartered in Velizy-Villacoublay, Versailles, and 脡lancourt, indicating a geographical cluster within the department. The founding dates show a mix of companies established in the late 1980s and early 2000s, alongside more recent ventures, suggesting a sustained growth in the IT and cybersecurity sectors over several decades.
馃嚝馃嚪 Yvelines 路 25 companies 路 Updated Nov 11, 2026
| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Saphir Group](https://www.tamtam.ai/c/saphir-group) (quariq.com)
Provides Industry 4.0 solutions, industrial automation, MES/MOM, PLM, data and AI, OT security for manufacturers, from strategy to execution globally. | IT Services and IT Consulting | 馃嚝馃嚪 Montigny-le-Bretonneux | 380 | 2024 |
| 2 | [Airbus Defence and Space Cyber](https://www.tamtam.ai/c/airbus-defence-and-space-cyber) (cyber.airbus.com)
Designing, developing, integrating, and deploying reliable cyber security solutions for defense, governmental, and institutional customers, leveraging 30 years of expertise. | IT Services and IT Consulting | 馃嚝馃嚪 脡lancourt | 308 | |
| 3 | [act digital EMEA - Alter Solutions](https://www.tamtam.ai/c/act-digital-emea-alter-solutions) (actdigital.com)
AI-first multinational technology company providing customized, scalable solutions with local agility and global expertise to create business value. | IT Services and IT Consulting | 馃嚝馃嚪 Versailles | 284 | 2006 |
| 4 | [Cegedim Outsourcing](https://www.tamtam.ai/c/cegedim-outsourcing) (cegedim-outsourcing.fr)
Specializes in IT and BPO services with strong technological partnerships, providing high-level technical expertise and independent consulting. | IT Services and IT Consulting | 馃嚝馃嚪 Velizy-Villacoublay | 230 | |
| 5 | [TVH Consulting](https://www.tamtam.ai/c/tvh-consulting) (tvhconsulting.fr)
An international software company specializing in ERP solutions, systems integration, and industry-specific solutions for various verticals globally | IT Services and IT Consulting | 馃嚝馃嚪 Maisons-Laffitte | 221 | 2003 |
| 6 | [M茅diane Syst猫me](https://www.tamtam.ai/c/mediane-systeme) (medianesysteme.com)
Specializes in custom secure real-time operating systems, private 5G networks, embedded AI, cybersecurity, and industrial network solutions. | Software Development | 馃嚝馃嚪 Le Pecq | 213 | 1989 |
| 7 | [ERCOM](https://www.tamtam.ai/c/ercom) (thalesgroup.com)
Provides cutting-edge cybersecurity and communication network solutions, including certified secure mobile communication, end-to-end encrypted data sharing, and secure messaging applications for professionals. | Computer and Network Security | 馃嚝馃嚪 Velizy-Villacoublay | 170 | 1986 |
| 8 | [GROUPE ROS DIGITAL](https://www.tamtam.ai/c/groupe-ros-digital) (rosdigital.fr)
A comprehensive group offering printing solutions, IT services, cloud storage, telecom solutions, communication products, and LED lighting expertise with dedicated specialists in each field | IT Services and IT Consulting | 馃嚝馃嚪 Chatou | 136 | 2001 |
| 9 | [NowBrains](https://www.tamtam.ai/c/nowbrains) (nowbrains.com)
Specializing in digital transformation and IT expertise for small and medium-sized enterprises, offering services in IT infrastructure, cybersecurity, digital strategy, and more Helping businesses accelerate their potential | IT Services and IT Consulting | 馃嚝馃嚪 脡lancourt | 105 | 2003 |
| 10 | [CA-SILCA](https://www.tamtam.ai/c/ca-silca)
IT production services for Groupe Cr茅dit Agricole, including infrastructure management, cloud solutions, big data, SOC operations, and user services | IT Services and IT Consulting | 馃嚝馃嚪 Guyancourt | 83 | 2005 |
| 11 | [Tersedia](https://www.tamtam.ai/c/tersedia) (tersedia.fr)
Provider of IT solutions specializing in global infrastructure distribution, storage, business continuity, and virtualized infrastructure, offering expertise and personalized service | IT Services and IT Consulting | 馃嚝馃嚪 Chatou | 75 | 1996 |
| 12 | [FraudBuster](https://www.tamtam.ai/c/fraudbuster) (fraudbuster.mobi)
Antifraud services for mobile network operators worldwide with disruptive approach and unique solutions like SIMBuster, and MoMoSe. | Telecommunications | 馃嚝馃嚪 Velizy-Villacoublay | 39 | 2010 |
| 13 | [Vistory](https://www.tamtam.ai/c/vistory) (vistory.com)
Development of cybersecurity software leveraging blockchain, cloud, and big data technologies to enable digital transformation and industry disruption. | Program Development | 馃嚝馃嚪 Velizy-Villacoublay | 38 | 2015 |
| 14 | [SI4YOU](https://www.tamtam.ai/c/si4you) (si-4you.com)
Provides comprehensive IT services including managed IT, cybersecurity, telephony, and custom web application development, guiding businesses through digital transformation with expertise and support. | IT Services and IT Consulting | 馃嚝馃嚪 Versailles | 36 | 2005 |
| 15 | [MTI France SAS](https://www.tamtam.ai/c/mti-france-sas) (fr.mti.com)
Provides tailored IT solutions and services in datacentre, security, and managed services with global experience and industry best practices. | IT Services and IT Consulting | 馃嚝馃嚪 Croissy-sur-Seine | 35 | 1988 |
| 16 | [SECUREWAY](https://www.tamtam.ai/c/secureway) (secureway.fr)
Providing specialized consulting for SAP system compliance with security and regulatory requirements, focusing on authorization management and GRC implementation for businesses. | IT Services and IT Consulting | 馃嚝馃嚪 Versailles | 24 | 2007 |
| 17 | [CENTHYS](https://www.tamtam.ai/c/centhys) (centhys.com)
Assists and guides leaders and stakeholders in cybersecurity and IT transformation, offering consulting, security and network integration, and managed services. | IT Services and IT Consulting | 馃嚝馃嚪 Velizy-Villacoublay | 23 | 2022 |
| 18 | [ALEZ PC PRESTATAIRE INFORMATIQUE](https://www.tamtam.ai/c/alez-pc-prestataire-informatique) (alezpc.com)
Provides IT infrastructure maintenance, security solutions, server management, data protection, compliance, and personalized IT training for businesses. | Computer and Network Security | 馃嚝馃嚪 Croissy-sur-Seine | 22 | 2005 |
| 19 | [Equipages](https://www.tamtam.ai/c/equipages) (equipages.fr)
Equipages specializes in building network and security infrastructure, supplying materials, deployment, maintenance, and providing expert assistance for major accounts with dedication and reliability | Computer and Network Security | 馃嚝馃嚪 Voisins-le-Bretonneux | 22 | 1998 |
| 20 | [SecInfra](https://www.tamtam.ai/c/secinfra) (secinfra.fr)
Dedicated security infrastructure player, assisting companies in securing their IT infrastructure, offering consulting, managed services, audits, and incident response for robust cybersecurity. | Computer and Network Security | 馃嚝馃嚪 Versailles | 19 | 2018 |
| 21 | [Insyncom](https://www.tamtam.ai/c/insyncom) (insyncom.fr)
Insyncom specializes in IT security and infrastructure, offering managed cloud solutions and technical support for clients undergoing digital transformation | Computer and Network Security | 馃嚝馃嚪 Le Pecq | 15 | 2014 |
| 22 | [Intuitem](https://www.tamtam.ai/c/intuitem) (intuitem.com)
Company creates cybersecurity software, focusing on governance, risk management, and compliance, using expertise in cloud, data, and AI to help organizations manage cyber challenges. | IT Services and IT Consulting | 馃嚝馃嚪 Velizy-Villacoublay | 14 | 2018 |
| 23 | [Oxibox](https://www.tamtam.ai/c/oxibox) (oxibox.com)
A plug-and-protect cyber-resilience solution that guarantees recovery after any disaster by automating data classification, isolation of backups from production network, and utilizing artificial intelligence | Computer and Network Security | 馃嚝馃嚪 Guyancourt | 10 | 2016 |
| 24 | [Bull Nederland](https://www.tamtam.ai/c/bull-nederland) (atos.net)
A leading provider of secure IT systems, focusing on high-quality solutions for efficient business operations in sectors like retail, manufacturing, government, and finance | IT Services and IT Consulting | 馃嚝馃嚪 Les Clayes-sous-Bois | 6 | 1948 |
| 25 | [ResoSafe](https://www.tamtam.ai/c/resosafe) (groupe-ros.com)
A data security specialist for over 25 years, providing products for protecting data, workstations, email communications, and networks | IT Services and IT Consulting | 馃嚝馃嚪 Chatou | 3 | 1995 |
## 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 Yvelines department
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- [Family-owned companies in the Yvelines department](https://www.tamtam.ai/l/family-owned-companies-yvelines) (36)
## The same list elsewhere in France
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- [Cybersecurity companies in the Nord department](https://www.tamtam.ai/l/cybersecurity-companies-nord) (30)
- [Cybersecurity companies in Pays de la Loire](https://www.tamtam.ai/l/cybersecurity-companies-pays-de-la-loire) (28)
- [Cybersecurity companies in the Haute-Garonne department](https://www.tamtam.ai/l/cybersecurity-companies-haute-garonne) (27)
- [Cybersecurity companies in the Ille-et-Vilaine department](https://www.tamtam.ai/l/cybersecurity-companies-ille-et-vilaine) (25)
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Source: https://www.tamtam.ai/l/cybersecurity-companies-yvelines