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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).

🇫🇷 Seine-Maritime30 companiesUpdated Nov 12, 2026

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.

#CompanyIndustryHeadquarters EmployeesFounded
1
Ceacomnormandie.ceacom.fr

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 Maintenancealpha.fr

Company specializing in oil and energy sector, providing services and solutions based in Port-de-Bouc, France.

Engineering Services 🇫🇷 Rouen 333 1986
3
Voxensvoxens.fr

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
SOCAPSsocaps.coop

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)groupeartemys.com

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 n/a
6
GH Connective | B Corpghconnective.com

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 Conseilgroupe-dec.fr

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
Helpeviahelpevia.fr

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 hrdominoconsulting.fr

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
Semaforsemafor.fr

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 BOXdb-structures.com

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
DEVOLISdevolis.com

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 EXPERTISEnewtonexpertise.com

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 Agilitydocaposte-agility.fr

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
REDLabredlab.io

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

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16
Actemium Le Havre Process Controlactemium.fr

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 LDatelierld.com

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 Serviceattineos.com

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

A company located in Le Petit Quevilly offering expertise services in an unspecified field

Accounting 🇫🇷 Le Petit-Quevilly 28 2007
20
ABEXEbizouard.com

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 EXTENSEcdhexpertises.com

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 Associéscab-longuemart.fr

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 Informatiquesiqual.fr

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 n/a
24
OFFICE NOTARIAL DU BOULINGRIN - Notaires à Rouen ⚖️office-du-boulingrin-rouen.notaires.fr

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-BOUTINcabinetboutin.fr

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'Affairesgomondavocats.com

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 n/a
27
SOCIETE EXPERTISE COMPTABLE SENAY CRAMPONexpertise-comptable-senay-crampon.com

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
wcomplywcomply.com

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 - Komizogroupekomizo.fr

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
Momentimomenti-recrutements.fr

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

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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 12, 2026.

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