# Professional services firms headquartered in the Seine-Maritime department

Tamtam tracks 51 professional services firms headquartered in the Seine-Maritime department. This list ranks the 30 largest by number of employees on LinkedIn, led by Ceacom, Alpha Maintenance and Voxens. Their median headcount is 42. Half of them were founded in 2006 or later. The most common headquarters are Rouen (13), Le Havre (3) and Mont-Saint-Aignan (3).

The professional services sector in Seine-Maritime features a range of mid-sized firms specializing in business consulting, IT, and engineering. Ceacom, based in Le Havre, provides customer relationship management services. Alpha Maintenance, located in Rouen, specializes in engineering services for the oil and energy sector. Voxens, also in Rouen, manages multichannel call center operations, while SOCAPS offers global technical assistance and consulting.

Key areas of activity include IT services and consulting, with companies like Artemys Normandie focusing on digital transformation and DEVOLIS providing Microsoft-certified cloud solutions. Accounting firms such as Groupe DEC and NEWTON EXPERTISE offer audit and legal services. A notable pattern is the concentration of headquarters in Rouen and Le Havre, reflecting these cities as key business hubs within the department.

🇫🇷 Seine-Maritime · 30 companies · Updated Nov 12, 2026

| # | Company | Industry | Headquarters | Employees | Founded |
|---|---|---|---|---|---|
| 1 | [Ceacom](https://www.tamtam.ai/c/ceacom) (normandie.ceacom.fr)<br>A customer relationship management company based in Le Havre, offering advisory and service jobs, actively involved in professional insertion networks and local events | Business Consulting and Services | 🇫🇷 Le Havre | 521 | 2006 |
| 2 | [Alpha Maintenance](https://www.tamtam.ai/c/alpha-maintenance) (alpha.fr)<br>Company specializing in oil and energy sector, providing services and solutions based in Port-de-Bouc, France. | Engineering Services | 🇫🇷 Rouen | 333 | 1986 |
| 3 | [Voxens](https://www.tamtam.ai/c/voxens) (voxens.fr)<br>Manages multichannel call center operations for telephone marketing, focusing on customer acquisition, loyalty, retention, and reactivation for both B2B and B2C clients. | Outsourcing and Offshoring Consulting | 🇫🇷 Rouen | 227 | 2009 |
| 4 | [SOCAPS](https://www.tamtam.ai/c/socaps) (socaps.coop)<br>Global leader in technical assistance and consulting services for various industries worldwide, focusing on skills development, ecological transition, and societal innovations | Engineering Services | 🇫🇷 Rouen | 189 | 1999 |
| 5 | [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 |  |
| 6 | [GH Connective \| B Corp](https://www.tamtam.ai/c/gh-connective-b-corp) (ghconnective.com)<br>This operational consulting firm assists businesses with optimization and transformation projects, covering quality, product development, supply chain, continuous improvement, and management control. | Business Consulting and Services | 🇫🇷 Le Havre | 119 | 2015 |
| 7 | [Groupe DEC, Diagnostic Expertise Conseil](https://www.tamtam.ai/c/groupe-dec-diagnostic-expertise-conseil) (groupe-dec.fr)<br>A group of specialists providing tailored solutions in Accounting, Audit, Legal, and IT services across multiple locations in France | Accounting | 🇫🇷 Mont-Saint-Aignan | 106 | 1990 |
| 8 | [Helpevia](https://www.tamtam.ai/c/helpevia) (helpevia.fr)<br>A team of 70 specialists supports private healthcare facilities in optimizing their purchasing processes through tailored advice and cost-effective solutions | Hospitals and Health Care | 🇫🇷 Rouen | 91 | 1980 |
| 9 | [Nextep hr](https://www.tamtam.ai/c/nextep-hr) (dominoconsulting.fr)<br>Specialized recruitment and direct approach for various companies, from small businesses to large groups, across diverse sectors for CDD, CDI, and temporary work. | Staffing and Recruiting | 🇫🇷 Rouen | 86 | 2013 |
| 10 | [Semafor](https://www.tamtam.ai/c/semafor) (semafor.fr)<br>A Human Wealth consultancy with over 25 years of experience, emphasizing that employees are more than just a resource for businesses | Business Consulting and Services | 🇫🇷 Rouen | 55 | 1996 |
| 11 | [DESIGN BOX](https://www.tamtam.ai/c/design-box) (db-structures.com)<br>Design Box provides excellent structural design services to clients, architects, and contractors, utilizing their in-depth theoretical and practical expertise in material science | Construction | 🇫🇷 Rouen | 49 | 2009 |
| 12 | [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 |
| 13 | [NEWTON EXPERTISE](https://www.tamtam.ai/c/newton-expertise) (newtonexpertise.com)<br>NEWTON Expertise is a 40-person company based in Mont-Saint-Aignan, offering expertise in accounting, audit, legal services, and business support for all stages of company life | Accounting | 🇫🇷 Mont-Saint-Aignan | 47 | 1945 |
| 14 | [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 |
| 15 | [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 |
| 16 | [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 |
| 17 | [ATELIER LD](https://www.tamtam.ai/c/atelier-ld) (atelierld.com)<br>Innovative urban planning solutions with a multidisciplinary team of engineers, landscapers, urban planners, and architects focusing on environmental quality and user benefit | Architecture and Planning | 🇫🇷 Bois-Guillaume | 30 | 2006 |
| 18 | [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 |
| 19 | [CAP EXPERTISE](https://www.tamtam.ai/c/cap-expertise)<br>A company located in Le Petit Quevilly offering expertise services in an unspecified field | Accounting | 🇫🇷 Le Petit-Quevilly | 28 | 2007 |
| 20 | [ABEXE](https://www.tamtam.ai/c/abexe) (bizouard.com)<br>An accounting firm located in Le Havre, France, specializing in providing financial services and support to businesses and individuals | Accounting | 🇫🇷 Le Havre | 26 | 2006 |
| 21 | [CDH EXTENSE](https://www.tamtam.ai/c/cdh-extense) (cdhexpertises.com)<br>Expertise, consulting, and training company specializing in agri-food, environmental, health, animal production, and agriculture risk management Trusted partner for insurance and businesses worldwide | Insurance | 🇫🇷 Bierville | 25 | 1999 |
| 22 | [Cabinet Longuemart Conseils et Associés](https://www.tamtam.ai/c/cabinet-longuemart-conseils-et-associes) (cab-longuemart.fr)<br>A team of two chartered accountants and 20 staff in downtown Rouen offer accounting, auditing, legal services, and business support | Accounting | 🇫🇷 Rouen | 25 | 1926 |
| 23 | [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 |  |
| 24 | [OFFICE NOTARIAL DU BOULINGRIN - Notaires à Rouen ⚖️](https://www.tamtam.ai/c/office-notarial-du-boulingrin-notaires-a-rouen) (office-du-boulingrin-rouen.notaires.fr)<br>Experts willing to assist with various projects led by Jean-Christophe PICOT, Laurent ALZAY, Guillaume POISSON-LECLERC, Bénédicte VUIGNER, Susy LEGRIX-QUEVAL, and Aude VANDENBULCKE | Legal Services | 🇫🇷 Rouen | 15 | 1804 |
| 25 | [CABINET FOLLET-BOUTIN](https://www.tamtam.ai/c/cabinet-follet-boutin) (cabinetboutin.fr)<br>Support for business owners and individuals with daily management, important decisions, tax declarations, administrative tasks, and financial advice. | Accounting | 🇫🇷 Aumale | 14 | 1981 |
| 26 | [Gomond Avocats d'Affaires](https://www.tamtam.ai/c/gomond-avocats-d-affaires) (gomondavocats.com)<br>Legal firm specializing in corporate law, litigation, and M&A Experienced team offers strategic legal advice, company restructuring, equity transactions, and more Leaders prioritize client interests | Law Practice | 🇫🇷 Rouen | 14 |  |
| 27 | [SOCIETE EXPERTISE COMPTABLE SENAY CRAMPON](https://www.tamtam.ai/c/societe-expertise-comptable-senay-crampon) (expertise-comptable-senay-crampon.com)<br>A Normandy-based accounting firm provides expert guidance and tools for business management since 1993 from their Fécamp and Le Havre offices | Accounting | 🇫🇷 Fécamp | 13 | 1993 |
| 28 | [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 |
| 29 | [Sarege Fideta Normandie - Komizo](https://www.tamtam.ai/c/sarege-fideta-normandie-komizo) (groupekomizo.fr)<br>A multidisciplinary team of dedicated professionals offering expertise in payroll, tax compliance, annual accounts, and long-term success strategies to various businesses and professionals | Accounting | 🇫🇷 Rouen | 12 | 2013 |
| 30 | [Momenti](https://www.tamtam.ai/c/momenti) (momenti-recrutements.fr)<br>Specialized recruitment agency in accounting, industry, IT, and construction/real estate, offering tailored support with a focus on perseverance, transparency, and ethics | Staffing and Recruiting | 🇫🇷 Mont-Saint-Aignan | 12 | 2020 |

## 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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## The same list elsewhere in France

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- [Professional services firms in the Hauts-de-Seine department](https://www.tamtam.ai/l/professional-services-firms-hauts-de-seine) (629)
- [Professional services firms in Provence-Alpes-Côte d'Azur](https://www.tamtam.ai/l/professional-services-firms-provence-alpes-cote-dazur) (433)
- [Professional services firms in the Rhône department](https://www.tamtam.ai/l/professional-services-firms-rhone) (400)
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- [Professional services firms in Hauts-de-France](https://www.tamtam.ai/l/professional-services-firms-hauts-de-france) (260)
- [Professional services firms in Pays de la Loire](https://www.tamtam.ai/l/professional-services-firms-pays-de-la-loire) (253)
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- [Professional services firms in the Haute-Garonne department](https://www.tamtam.ai/l/professional-services-firms-haute-garonne) (208)
- [Professional services firms in the Nord department](https://www.tamtam.ai/l/professional-services-firms-nord) (178)
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- [Professional services firms in Boulogne-Billancourt](https://www.tamtam.ai/l/professional-services-firms-boulogne-billancourt) (102)

## The same list elsewhere

- [Professional services firms in the world](https://www.tamtam.ai/l/professional-services-firms-in-the-world) (24,737)
- [Professional services firms in Europe](https://www.tamtam.ai/l/professional-services-firms-in-europe) (13,698)

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Source: https://www.tamtam.ai/l/professional-services-firms-seine-maritime