Company lists · Data refreshed September 2026

Top 25 Legacy system modernization firms based in France

Name: Legacy system modernization firms based in France
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 20, 2026 1,263 companies tracked

RevenueBase identified 1,263 legacy system modernization firms headquartered in France as of September 2026 and tracks 80,045 professional contacts across them, including 31,929 with verified work emails. Paris is the largest hub.

This list covers legacy system modernization 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 20, 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 20, 2026 86% judged on-target in blind review

1,263Companies

80,045Contacts tracked

31,929Verified emails

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The 25 largest legacy system modernization firms based in France

Ranked by team size

Top 25 of 1,263 legacy system modernization firms based in France, ranked by team size, largest first. Data refreshed Sep 20, 2026. RevenueBase Smart Search rates how each company's information relates to legacy system modernization 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	Sopra Steria	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	10001+	36,960 contacts →
	Indirect evidence “Sopra Steria, a major Tech player in Europe with employees in nearly 30 countries, is recognised for its consulting, digital services and solutions.” Source: RevenueBase Database · checked Sep 20, 2026
2	Wavestone	Indirect evidence	100-101 Terrasse Boieldieu, FranceHQ checked Sep 20, 2026	1,001-5,000	6,190 contacts →
	Indirect evidence “Wavestone is a leading consulting firm operating at the intersection of business and technology.” Source: RevenueBase Database · checked Sep 20, 2026
3	Groupe SII	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	10001+	4,928 contacts →
	Indirect evidence “Le groupe SII est une société d’ingénierie et de conseil en technologies (ICT) et une entreprise de services numériques (ESN) créée en 1979 par Bernard HUVÉ, ingénieur de…” Source: RevenueBase Database · checked Sep 20, 2026
4	Keyrus	Partial evidence	Levallois-perret, FranceHQ checked Sep 20, 2026	1,001-5,000	1,964 contacts →
	Partial evidence “At Keyrus, we help organizations move from experimental AI to industrialized AI, from isolated agents to orchestrated systems, and from insight to execution.” Source: RevenueBase Database · checked Sep 20, 2026
5	Infotel	Indirect evidence	Neuilly-sur-seine, FranceHQ checked Sep 20, 2026	1,001-5,000	1,735 contacts →
	Indirect evidence “Infotel accompagne les directions Informatiques et Métiers des grandes entreprises depuis 45 ans (Airbus, Air France, PSA, BNP Paribas, Banque de France ou encore BPCE, etc.).” Source: RevenueBase Database · checked Sep 20, 2026
6	Prodware	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	1,001-5,000	1,394 contacts →
	Indirect evidence “At Prodware, we believe that Trust, Audacity, and Passion are the driving forces behind meaningful digital transformation.” Source: RevenueBase Database · checked Sep 20, 2026
7	NIJI	Indirect evidence	Issy-les-moulineaux, FranceHQ checked Sep 20, 2026	1,001-5,000	1,256 contacts →
	Indirect evidence “Créée en septembre 2001, Niji est une société de conseil, de design et de mise en œuvre technologique, entièrement dédiée à la transformation numérique des entreprises et des…” Source: RevenueBase Database · checked Sep 20, 2026
8	Acensi	Indirect evidence	Courbevoie, FranceHQ checked Sep 20, 2026	1,001-5,000	844 contacts →
	Indirect evidence “You will be part of ACENSI network: 1650 co-workers involved in IS transformation projects at our clients through our multisectoral expertise.” Source: RevenueBase Database · checked Sep 20, 2026
9	Klanik	Indirect evidence	Marseille, FranceHQ checked Sep 20, 2026	501-1,000	585 contacts →
	Indirect evidence “KLANIK is a consulting company specialized in IT Engineering which accompanies its partners in their digital and technological projects.” Source: RevenueBase Database · checked Sep 20, 2026
10	Alteca	Indirect evidence	Villeurbanne, FranceHQ checked Sep 20, 2026	501-1,000	574 contacts →
	Indirect evidence “Alteca is a French IT & Digital services company created in 1996.” Source: RevenueBase Database · checked Sep 20, 2026
11	DCS Easyware	Indirect evidence	Lyon, FranceHQ checked Sep 20, 2026	1,001-5,000	532 contacts →
	Indirect evidence “Filiale du Groupe SYNERGIE, DCS SYNERGIE GROUP capitalise sur son histoire pour accompagner chaque jour les enjeux IT de ses clients.” Source: RevenueBase Database · checked Sep 20, 2026
12	Ippon Technologies	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	201-500	510 contacts →
	Indirect evidence “USING OUR COLLECTIVE ENERGY FOR POSITIVE TECHNOLOGY Ippon is a consulting and expertise firm, who is convinced that technology is a source of progress for society.” Source: RevenueBase Database · checked Sep 20, 2026
13	Zenika	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	501-1,000	430 contacts →
	Indirect evidence “Zenika is an IT consulting firm with 550 employees that helps companies with their digital transformation.” Source: RevenueBase Database · checked Sep 20, 2026
14	Audensiel	Indirect evidence	Boulogne-billancourt, FranceHQ checked Sep 20, 2026	1,001-5,000	417 contacts →
	Indirect evidence “Digital transformation company, business and technology consulting, Audensiel supports its clients in all business sectors in France and abroad in the following areas- Digital…” Source: RevenueBase Database · checked Sep 20, 2026
15	ITS Group S.A	Indirect evidence	Boulogne-billancourt, FranceHQ checked Sep 20, 2026	1,001-5,000	342 contacts →
	Indirect evidence “For over 20 years, ITS Group has supported companies in their digital transformation projects thanks to the strength of its specialized areas of expertise.” Source: RevenueBase Database · checked Sep 20, 2026
16	LÙKLA	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	501-1,000	331 contacts →
	Indirect evidence “Together, aiming higher and going further to unlock your potential.” Source: RevenueBase Database · checked Sep 20, 2026
17	Amiltone	Indirect evidence	Villeurbanne, FranceHQ checked Sep 20, 2026	201-500	314 contacts →
	Indirect evidence “Bienvenue chez Amiltone.” Source: RevenueBase Database · checked Sep 20, 2026
18	Inside	Indirect evidence	Toulouse, FranceHQ checked Sep 20, 2026	201-500	313 contacts →
	Indirect evidence “Inside est une société de conseil et de services numériques qui simplifie et accélère la transformation des entreprises, de la stratégie à la mise en œuvre, avec un objectif clair…” Source: RevenueBase Database · checked Sep 20, 2026
19	Cyllene	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	201-500	279 contacts →
	Indirect evidence “Chez Cyllene, on couvre le spectre complet de votre besoin en termes de : Conseils 🧬 Définition d’architectures Hébergement & Services managés Cybersécurité & Formations…” Source: RevenueBase Database · checked Sep 20, 2026
20	Ouidou	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	201-500	252 contacts →
	Indirect evidence “Fondée en 2017, Ouidou est une entreprise de services du numérique regroupant plus de 250 collaborateurs.” Source: RevenueBase Database · checked Sep 20, 2026
21	Theodo	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	501-1,000	236 contacts →
	Indirect evidence “A Theodo, toute notre énergie est tournée vers la satisfaction de nos clients.” Source: RevenueBase Database · checked Sep 20, 2026
22	AS International Group	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	501-1,000	204 contacts →
	Indirect evidence “Société du groupe Neurones, AS International Group soutient les entreprises dans leur transformation digitale en proposant des solutions informatiques innovantes.” Source: RevenueBase Database · checked Sep 20, 2026
23	Groupe SYD	Indirect evidence	Saint Herblain, FranceHQ checked Sep 20, 2026	201-500	198 contacts →
	Indirect evidence “Chez SYD, nous accompagnons depuis plus de 25 ans les entreprises : TPE, PME et grands comptes, tous secteurs confondus dans leur accélération digitale.” Source: RevenueBase Database · checked Sep 20, 2026
24	OXYL	Indirect evidence	Arcueil, FranceHQ checked Sep 20, 2026	51-200	198 contacts →
	Indirect evidence “Oxyl Groupe \| L’humain au cœur de la technologie Chez Oxyl Groupe, nous accompagnons les entreprises dans leurs transformations digitales avec une conviction simple : la…” Source: RevenueBase Database · checked Sep 20, 2026
25	Wemanity Reply Paris	Indirect evidence	Paris, FranceHQ checked Sep 20, 2026	201-500	178 contacts →
	Indirect evidence “Wemanity Reply is a consulting and delivery firm specialized in technological, organizational, and cultural transformation.” Source: RevenueBase Database · checked Sep 20, 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: legacy system modernization 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 legacy system modernization firms.
Partial evidence: Its own public description names part of legacy system modernization firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name legacy system modernization 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 1,263 legacy system modernization firms based in France

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Legacy system modernization firms based in France at a glance

As of Sep 20, 2026

39.9%Verified-email coverage

63.4Average contacts per company

1-10Median size (employees)

31.4%Largest-city concentration · Paris

Sep 20, 2026Page data refreshed

Companies by employee count

1-10

705

11-50

366

51-200

129

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured worldwide rather than for France, so it is reported there. Company counts and contact totals on this page are exact for France, over 1,263 companies.

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 legacy system modernization 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 “legacy system modernization 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 legacy system modernization 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 legacy system modernization 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, 31,929 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 20, 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.

Legacy system modernization firms by metro

Legacy system modernization firms in Paris396
Legacy system modernization firms in Lyon44

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 legacy system modernization 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 legacy system modernization firms are there based in France?

RevenueBase identified 1,263 legacy system modernization 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?

Sopra Steria, headquartered in Paris, tops this list with the largest team on record.

Which city has the most legacy system modernization firms?

Paris leads with 396 headquartered companies, followed by Lyon (44) and Lille (22).

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 31,929 verified decision-maker contacts tracked across these 1,263 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 20, 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.