# List of IT services companies in the Seine-Maritime department

Tamtam tracks 40 IT services companies headquartered in the Seine-Maritime department. This list ranks the 30 largest by number of employees on LinkedIn, led by Attineos Applications, Artemys Normandie (groupe Artemys) and TOSHIBA Centre Grand Ouest. Their median headcount is 30. Half of them were founded in 2011 or later. The most common headquarters are Rouen (9), Mont-Saint-Aignan (3) and Le Havre (2).

The companies listed in Seine-Maritime are primarily IT services and software development firms. These are mostly mid-sized companies, with headcounts ranging from 30 to 149 employees. They include Attineos Applications, a digital services company, and Artemys Normandie, which focuses on digital transformation. DEVOLIS offers cloud migration and collaborative tools, while FTEL specializes in web and mobile software development.

A notable pattern is the concentration of these companies in the Rouen metropolitan area. Many are headquartered in Rouen itself, such as Attineos Applications and ACE Service, or in nearby towns like Sotteville-lès-Rouen (TOSHIBA Centre Grand Ouest, Docaposte Agility) and Le Petit-Quevilly (DEVOLIS, REDLab).

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

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Attineos Applications](https://www.tamtam.ai/c/attineos-applications) (attineos.com)<br>Attineos is a unique digital services company, focusing on client and employee satisfaction through expertise, technology, growth, and support | Technology, Information and Internet | 🇫🇷 Rouen | 149 | 2014 |
| 2 | [Artemys Normandie (groupe Artemys)](https://www.tamtam.ai/c/artemys-normandie-groupe-artemys) (groupeartemys.com)<br>The company offers a range of digital transformation services, with a focus on infrastructure, Cloud, BI, cybersecurity, and IT project management | IT Services and IT Consulting | 🇫🇷 Isneauville | 135 |  |
| 3 | [TOSHIBA Centre Grand Ouest](https://www.tamtam.ai/c/toshiba-centre-grand-ouest) (toshibatec.fr)<br>Innovative company offering cutting-edge solutions tailored to businesses of all sizes, focused on understanding and addressing client needs with proven or innovative technologies | Technology, Information and Internet | 🇫🇷 Sotteville-lès-Rouen | 94 |  |
| 4 | [Attineos Infrastructures](https://www.tamtam.ai/c/attineos-infrastructures) (attineos.com)<br>Offers IT systems and network services, focusing on human capital to support, operate, and transform information systems for clients. | IT Services and IT Consulting | 🇫🇷 Mont-Saint-Aignan | 75 | 2017 |
| 5 | [DEVOLIS](https://www.tamtam.ai/c/devolis) (devolis.com)<br>DEVOLIS is a certified Microsoft partner offering tailored solutions for cloud migration, collaborative tools, app development, Big Data integration, and intelligent bots | IT Services and IT Consulting | 🇫🇷 Le Petit-Quevilly | 49 | 2007 |
| 6 | [Docaposte Agility](https://www.tamtam.ai/c/docaposte-agility) (docaposte-agility.fr)<br>Consulting firm driving agile and digital transformation for businesses Specializing in productivity enhancement and change success through tailored solutions and expertise | IT Services and IT Consulting | 🇫🇷 Sotteville-lès-Rouen | 45 | 2011 |
| 7 | [Napsis](https://www.tamtam.ai/c/napsis) (napsis.fr)<br>The company specializes in creating lasting relationships with businesses by providing end-to-end telecom solutions tailored to their specific needs | Telecommunications | 🇫🇷 Le Havre | 43 | 2017 |
| 8 | [REDLab](https://www.tamtam.ai/c/redlab) (redlab.io)<br>REDLab transforms raw data into valuable insights for businesses, offering tailored solutions to enhance operational efficiency, risk management, and customer experience through data analysis | IT Services and IT Consulting | 🇫🇷 Le Petit-Quevilly | 42 | 2017 |
| 9 | [Enovea, votre partenaire logiciel](https://www.tamtam.ai/c/enovea-votre-partenaire-logiciel) (enovea.net)<br>Develops digital projects like 3D configurators and ERP integration. Publishes software for real-time matching, data reconciliation, and connected object data analysis. | Software Development | 🇫🇷 Mont-Saint-Aignan | 42 | 2008 |
| 10 | [OASIS Projet](https://www.tamtam.ai/c/oasis-projet) (oasis-projet.com)<br>Agency specializing in e-commerce site creation, offering e-business solutions, training, and support for online business growth and management. | Technology, Information and Internet | 🇫🇷 Saint-Étienne-du-Rouvray | 39 | 2003 |
| 11 | [FTEL](https://www.tamtam.ai/c/ftel) (ftel.fr)<br>Specialized in web & mobile software development since 1999, creating customized applications, offering hosting, maintenance services, and developing various software solutions | Software Development | 🇫🇷 Rouen | 35 | 1999 |
| 12 | [Actemium Le Havre Process Control](https://www.tamtam.ai/c/actemium-le-havre-process-control) (actemium.fr)<br>Specializing in project management, automation, and industrial IT solutions, we enhance efficiency for industrial partners through process expertise and custom software solutions | Automation Machinery Manufacturing | 🇫🇷 Port-Jérôme-sur-Seine | 34 | 1981 |
| 13 | [BearStudio](https://www.tamtam.ai/c/bearstudio) (bearstudio.fr)<br>The BearStudio offers R&D support for innovative digital projects, from MVP design to technology implementation, with a hands-on approach in website, web app, and mobile app development | IT Services and IT Consulting | 🇫🇷 Le Petit-Quevilly | 33 | 2016 |
| 14 | [Groupe FrameIP](https://www.tamtam.ai/c/groupe-frameip) (groupe-frameip.fr)<br>A group of IT companies specializing in enterprise networks, telecommunications, system infrastructure, and cybersecurity for professional clientele | IT Services and IT Consulting | 🇫🇷 Eslettes | 33 |  |
| 15 | [ACE Service](https://www.tamtam.ai/c/ace-service) (attineos.com)<br>Established in 2001, this company specializes in information systems security, with a focus on proactive monitoring and technological innovation for clients | Computer and Network Security | 🇫🇷 Rouen | 30 | 2001 |
| 16 | [DIGIT](https://www.tamtam.ai/c/digit) (groupedigit.com)<br>Providing software development, system interoperability, data valorization, cost control, encryption, and IT team reinforcement with a focus on responsible digital practices. | IT Services and IT Consulting | 🇫🇷 Le Petit-Quevilly | 29 | 2017 |
| 17 | [Caux Formatique](https://www.tamtam.ai/c/caux-formatique) (cauxformatique.fr)<br>Specialized in management software, providing implementation, training, and support services for accounting, sales, payroll systems to professional clients Also offers IT maintenance | Software Development | 🇫🇷 Sainte-Marie-des-Champs | 27 | 1988 |
| 18 | [ASSIST EVOLUTION](https://www.tamtam.ai/c/assist-evolution) (assist-evolution.com)<br>A consultancy specializing in management and information systems, fostering strong partnerships with clients to enhance organizational efficiency | Information Services | 🇫🇷 Rouen | 26 | 2005 |
| 19 | [Human to Computer](https://www.tamtam.ai/c/human-to-computer) (humantocomputer.com)<br>Specializing in creating personalized and growth-driven web solutions since 2006 Services include website creation/redesign, web design, development, and e-marketing, emphasizing collaborative project methods | Technology, Information and Internet | 🇫🇷 Rouen | 25 | 2006 |
| 20 | [Henosis](https://www.tamtam.ai/c/henosis) (henosis.fr)<br>Henosis provides consulting, project management, and technical support services for large corporate clients in Normandy and the Paris region, focusing on IT infrastructure | IT Services and IT Consulting | 🇫🇷 Rouen | 24 | 2015 |
| 21 | [Fine Tech](https://www.tamtam.ai/c/fine-tech) (fine-tech.fr)<br>Fine Tech offers accompaniment services for cloud migration, Sage 100c management products, GDPR compliance analysis, and document management with a focus on innovative solutions for client satisfaction | IT Services and IT Consulting | 🇫🇷 Rouen | 23 | 2018 |
| 22 | [SIQUAL Informatique](https://www.tamtam.ai/c/siqual-informatique) (siqual.fr)<br>Specializing in web solutions and information systems management, this company serves small businesses to large industrial groups with a focus on agility and client proximity | IT Services and IT Consulting | 🇫🇷 Le Petit-Quevilly | 22 |  |
| 23 | [ADMI France devient Blue](https://www.tamtam.ai/c/admi-france-devient-blue) (bt-blue.com)<br>Specializing in IT maintenance, cloud computing, telecoms, and system redesign, experts provide advice and technical know-how for seamless information management | IT Services and IT Consulting | 🇫🇷 Gonfreville-l'Orcher | 22 | 1996 |
| 24 | [SIXMON](https://www.tamtam.ai/c/sixmon) (sixmon.net)<br>SIXMON specializes in developing complex web and mobile platforms, focusing on quality, scalability, and performance, with a passion for technology | IT Services and IT Consulting | 🇫🇷 Le Havre | 22 | 2014 |
| 25 | [Artemys Agil-IT (groupe Artemys)](https://www.tamtam.ai/c/artemys-agil-it-groupe-artemys) (groupeartemys.com)<br>Support large enterprises with IT infrastructure, cloud, DevOps, user experience, BI, security, and training across multiple French regions and Belgium. | IT Services and IT Consulting | 🇫🇷 Isneauville | 20 |  |
| 26 | [Ceriel - Solutions d'infrastructure & Services IT](https://www.tamtam.ai/c/ceriel-solutions-d-infrastructure-and-services-it) (ceriel.fr)<br>A digital services company based in Rouen, Le Havre, and Caen since 1990, providing expertise in IT infrastructure and services to drive growth and competitiveness | IT Services and IT Consulting | 🇫🇷 Mont-Saint-Aignan | 18 | 1990 |
| 27 | [FrameIP](https://www.tamtam.ai/c/frameip) (frameip.fr)<br>FrameIP offers expertise in networking, security, telephony, and more, providing tailored solutions for infrastructure projects and professional training programs | Computer Networking Products | 🇫🇷 Eslettes | 16 | 2007 |
| 28 | [DEAPDATA](https://www.tamtam.ai/c/deapdata) (deapdata.com)<br>A consulting firm specializing in business intelligence & big data, assisting clients with data management, visualization, analysis, science, and engineering projects Serving diverse industries | IT Services and IT Consulting | 🇫🇷 Rouen | 14 | 2016 |
| 29 | [wcomply](https://www.tamtam.ai/c/wcomply) (wcomply.com)<br>Provides specialized advisory services for cybersecurity, risk, and compliance, focusing on SAP system protection, cloud migrations, identity management, and financial license optimization. | IT Services and IT Consulting | 🇫🇷 Rouen | 13 | 2019 |
| 30 | [KEYVEO](https://www.tamtam.ai/c/keyveo) (keyveo.com)<br>Specializing in virtual tours and immersive technologies, the company creates innovative digital projects for businesses, educational institutions, and municipalities with prestigious clients worldwide | Software Development | 🇫🇷 Le Petit-Quevilly | 13 | 2014 |

## 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-Maritime department

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- [Healthcare providers in the Seine-Maritime department](https://www.tamtam.ai/l/healthcare-providers-seine-maritime) (34)
- [Logistics companies in the Seine-Maritime department](https://www.tamtam.ai/l/logistics-companies-seine-maritime) (34)
- [Financial services firms in the Seine-Maritime department](https://www.tamtam.ai/l/financial-services-firms-seine-maritime) (32)
- [IT Services and IT Consulting companies in the Seine-Maritime department](https://www.tamtam.ai/l/it-services-and-it-consulting-companies-seine-maritime) (30)
- [Real Estate companies in the Seine-Maritime department](https://www.tamtam.ai/l/real-estate-companies-seine-maritime) (30)
- [Higher Education companies in the Seine-Maritime department](https://www.tamtam.ai/l/higher-education-companies-seine-maritime) (28)
- [Software Development companies in the Seine-Maritime department](https://www.tamtam.ai/l/software-development-companies-seine-maritime) (28)
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- [Consulting firms in the Seine-Maritime department](https://www.tamtam.ai/l/consulting-firms-seine-maritime) (26)
- [Hospitals and Health Care companies in the Seine-Maritime department](https://www.tamtam.ai/l/hospitals-and-health-care-companies-seine-maritime) (25)

## The same list elsewhere in France

- [IT services companies in France](https://www.tamtam.ai/l/it-services-companies-france) (5,000)
- [IT services companies in Île-de-France](https://www.tamtam.ai/l/it-services-companies-ile-de-france) (2,624)
- [IT services companies in the Hauts-de-Seine department](https://www.tamtam.ai/l/it-services-companies-hauts-de-seine) (737)
- [IT services companies in Auvergne-Rhône-Alpes](https://www.tamtam.ai/l/it-services-companies-auvergne-rhone-alpes) (519)
- [IT services companies in the Rhône department](https://www.tamtam.ai/l/it-services-companies-rhone) (286)
- [IT services companies in Occitanie](https://www.tamtam.ai/l/it-services-companies-occitanie) (280)
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- [IT services companies in Pays de la Loire](https://www.tamtam.ai/l/it-services-companies-pays-de-la-loire) (205)
- [IT services companies in Nouvelle-Aquitaine](https://www.tamtam.ai/l/it-services-companies-nouvelle-aquitaine) (194)
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- [IT services companies in the Bouches-du-Rhône department](https://www.tamtam.ai/l/it-services-companies-bouches-du-rhone) (155)
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- [IT services companies in Brittany](https://www.tamtam.ai/l/it-services-companies-brittany) (113)
- [IT services companies in the Val-de-Marne department](https://www.tamtam.ai/l/it-services-companies-val-de-marne) (101)
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- [IT services companies in Boulogne-Billancourt](https://www.tamtam.ai/l/it-services-companies-boulogne-billancourt) (125)
- [IT services companies in Toulouse](https://www.tamtam.ai/l/it-services-companies-toulouse) (119)
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Source: https://www.tamtam.ai/l/it-services-companies-seine-maritime