Company lists · Data refreshed September 2026

Top 25 Custom software firms based in France

Name: Custom software firms based in France
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 24, 2026 1,748 companies tracked

RevenueBase identified 1,748 custom software firms headquartered in France as of September 2026 and tracks 15,420 professional contacts across them, including 5,697 with verified work emails and 417 with mobile numbers. Paris is the largest hub.

This list covers custom software firms headquartered in France, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 24, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 24, 2026 86% judged on-target in blind review

1,748Companies

15,420Contacts tracked

5,697Verified emails

417Mobile numbers

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The 25 largest custom software firms based in France

Ranked by team size

Top 25 of 1,748 custom software firms based in France, ranked by team size, largest first. Data refreshed Sep 24, 2026. RevenueBase Smart Search rates how each company's information relates to custom software firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	SFEIR	Indirect evidence	Neuilly-sur-seine, FranceHQ checked Sep 24, 2026	501-1,000	904 contacts →
	Indirect evidence “SFEIR est une Société d’expertise spécialisée dans le développement d’applications sous toutes leurs formes ( web, mobile, IOT, cloud, data, etc.).” Source: RevenueBase Database · checked Sep 24, 2026
2	CELAD	Partial evidence	Toulouse, FranceHQ checked Sep 24, 2026	1,001-5,000	570 contacts →
	Partial evidence “Consulting and Engineering in innovative technology Celad is a global software engineering company with over 1200 engineers.” Source: RevenueBase Database · checked Sep 24, 2026
3	Avanquest	Partial evidence	Courbevoie, FranceHQ checked Sep 24, 2026	201-500	315 contacts →
	Partial evidence “At Avanquest, we develop software that makes digital simpler, smarter and more useful.” Source: RevenueBase Database · checked Sep 24, 2026
4	Infogene	Indirect evidence	Neuilly-sur-seine, FranceHQ checked Sep 24, 2026	501-1,000	291 contacts →
	Indirect evidence “INFOGENE est une ESN spécialisée dans 3 domaines principaux (en AMOA et MOE): DIGITAL: Notre savoir faire : Conseil, architecture logiciel, conception, développement, maintenance…” Source: RevenueBase Database · checked Sep 24, 2026
5	Kaizen Solutions KZS	Indirect evidence	Montbonnot-saint-martin, FranceHQ checked Sep 24, 2026	201-500	261 contacts →
	Indirect evidence “Nous sommes une ESN (entreprise de services numériques) spécialisée dans la conception, le développement et la maintenabilité de solutions informatiques, techniques et…” Source: RevenueBase Database · checked Sep 24, 2026
6	Avisto	Partial evidence	Valbonne, FranceHQ checked Sep 24, 2026	201-500	226 contacts →
	Partial evidence “The software development: your passion, our profession.” Source: RevenueBase Database · checked Sep 24, 2026
7	XELYA	Indirect evidence	Saint-cloud, FranceHQ checked Sep 24, 2026	201-500	224 contacts →
	Indirect evidence “Editeur de logiciels métiers SaaS, nous fournissons des solutions technologiques innovantes, du conseil et de la formation pour dompter la complexité du métier de nos clients.” Source: RevenueBase Database · checked Sep 24, 2026
8	Takima	Indirect evidence	Bagneux, FranceHQ checked Sep 24, 2026	51-200	222 contacts →
	Indirect evidence “Whether dealing with Opensource, B2B, B2C mobile apps, intranets or HA infrastructures, the same approach remains: Understanding the context, qualifying the use case, determining…” Source: RevenueBase Database · checked Sep 24, 2026
9	AXYUS	Indirect evidence	Issy-les-moulineaux, FranceHQ checked Sep 24, 2026	51-200	170 contacts →
	Indirect evidence “Une SSII avec de vraies valeurs."S'engager au forfait, respecter, les attentes de nos clients, leur budget en favorisant notamment la réutilisation affichée de nos composants…” Source: RevenueBase Database · checked Sep 24, 2026
10	Augusta Reeves	Indirect evidence	Paris, FranceHQ checked Sep 24, 2026	51-200	150 contacts →
	Indirect evidence “Augusta Reeves was founded in 1998 as an IT services company with three areas of expertise: 1.” Source: RevenueBase Database · checked Sep 24, 2026
11	Omnilog	Indirect evidence	Boulogne-billancourt, FranceHQ checked Sep 24, 2026	201-500	139 contacts →
	Indirect evidence “Nos mots-clés :#Médias,#Technos,#Convivialité Plus qu'une SSII, Omnilog est une équipe de 300 ingénieurs spécialisés dans le développement web et mobile et les technologies.NET…” Source: RevenueBase Database · checked Sep 24, 2026
12	SCUB	Indirect evidence	Angoulême, FranceHQ checked Sep 24, 2026	51-200	127 contacts →
	Indirect evidence “Scub est une société de service en informatique qui a pour but de fournir du conseil et de développer des applications spécifiques afin de résoudre vos problématiques les plus…” Source: RevenueBase Database · checked Sep 24, 2026
13	IS Technologies	Indirect evidence	Courbevoie Cedex, FranceHQ checked Sep 24, 2026	n/a	127 contacts →
	Indirect evidence “IS Technologies est une société de conseils et de services en informatique basée à La Défense.” Source: RevenueBase Database · checked Sep 24, 2026
14	Web-Atrio	Indirect evidence	Paris, FranceHQ checked Sep 24, 2026	51-200	111 contacts →
	Indirect evidence “Bienvenue chez WEB-ATRIO, l’#ESN qui change la donne!” Source: RevenueBase Database · checked Sep 24, 2026
15	Tritux	Indirect evidence	Paris, FranceHQ checked Sep 24, 2026	51-200	108 contacts →
	Indirect evidence “Depuis sa création en 2006, TRITUX a développé une expertise et un savoir faire lui permettant de mener à bien tous ses projets de l’amont à l’aval.” Source: RevenueBase Database · checked Sep 24, 2026
16	Spark-It	Partial evidence	La Défense 5, FranceHQ checked Sep 24, 2026	51-200	105 contacts →
	Partial evidence “Spark-it is an expert in software architecture.” Source: RevenueBase Database · checked Sep 24, 2026
17	Castelis	Indirect evidence	Ivry Sur Seine, FranceHQ checked Sep 24, 2026	51-200	97 contacts →
	Indirect evidence “Castelis, c'est l'histoire d'une entreprise en croissance continue.” Source: RevenueBase Database · checked Sep 24, 2026
18	Nextoo	Indirect evidence	Roubaix, FranceHQ checked Sep 24, 2026	51-200	95 contacts →
	Indirect evidence “Eh non,"Développeurs de progrès", n’est pas qu'un joli slogan pour nos T-shirts; c'est une véritable philosophie.” Source: RevenueBase Database · checked Sep 24, 2026
19	Toshiba Centre Grand Ouest	Indirect evidence	Sotteville-lès-rouen, FranceHQ checked Sep 24, 2026	51-200	95 contacts →
	Indirect evidence “Toshiba Centre Grand Ouest met sa passion de l'innovation au service de ses clients en proposant des solutions à la pointe de la technologie, utiles à la vie des entreprises…” Source: RevenueBase Database · checked Sep 24, 2026
20	The Codingmachine	Indirect evidence	Paris, FranceHQ checked Sep 24, 2026	51-200	93 contacts →
	Indirect evidence “The Coding Machine is an IT company that provides bespoke web & mobile development.” Source: RevenueBase Database · checked Sep 24, 2026
21	6tm	Indirect evidence	Rennes, FranceHQ checked Sep 24, 2026	51-200	91 contacts →
	Indirect evidence “6TM accompagne ses clients vers un monde toujours plus communicant grâce à ses solutions web, mobiles et logiciels.” Source: RevenueBase Database · checked Sep 24, 2026
22	4sh	Indirect evidence	Le Haillan, FranceHQ checked Sep 24, 2026	51-200	85 contacts →
	Indirect evidence “4SH est une entreprise de services du numérique.” Source: RevenueBase Database · checked Sep 24, 2026
23	Simphonis	Indirect evidence	Beaucouzé, FranceHQ checked Sep 24, 2026	51-200	84 contacts →
	Indirect evidence “Unlock Your Digital Potential with SIMPHONIS!” Source: RevenueBase Database · checked Sep 24, 2026
24	SERLI	Indirect evidence	Chasseneuil-du-poitou, FranceHQ checked Sep 24, 2026	51-200	78 contacts →
	Indirect evidence “If you’re looking for a team who are up to the challenges of your project, you found it!” Source: RevenueBase Database · checked Sep 24, 2026
25	Bocasay	Indirect evidence	Neuilly-sur-seine, FranceHQ checked Sep 24, 2026	51-200	75 contacts →
	Indirect evidence “BOCASAY est une entreprise de services du numérique (ESN / SSII) spécialisée dans le développement web et applicatif.” Source: RevenueBase Database · checked Sep 24, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: custom software firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names custom software firms.
Partial evidence: Its own public description names part of custom software firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name custom software firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 1,748 custom software firms based in France

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Custom software firms based in France at a glance

As of Sep 24, 2026

36.9%Verified-email coverage

2.7%Mobile-number coverage

8.8Average contacts per company

1-10Median size (employees)

20.1%Largest-city concentration · Paris

Sep 24, 2026Page data refreshed

Companies by employee count

1-10

1,310

11-50

347

51-200

201-500

501-1,000

1,001-5,000

10001+

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 26.0d

4,3530–30

1,25431–60

6361–90

290–180

25180+

Company record updated

Median 79.0d

00–30

4,10131–60

7,01861–90

3,42790–180

874180+

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among custom software firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in France whose own description of what they do matches “custom software firms”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names custom software firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among custom software firms, and records with no verified work email. Companies headquartered outside France are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking: Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification: Every listed company carries at least one verified work email, 5,697 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 24, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Custom software firms by metro

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names custom software firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many custom software firms are there based in France?

RevenueBase identified 1,748 custom software firms headquartered in France as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

SFEIR, headquartered in Neuilly-Sur-Seine, tops this list with the largest team on record.

Which city has the most custom software firms?

Paris leads with 352 headquartered companies, followed by Lyon (72) and Toulouse (45).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 5,697 verified decision-maker contacts tracked across these 1,748 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 24, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.