Top 15 Legacy System Modernization Companies in France

Organizations running aging core systems often face rising maintenance costs, brittle integrations, and an inability to roll out new features quickly. When hiring a partner for legacy system modernization, buyers should compare technical approach, proven experience with comparable platforms, cloud and on‑premise migration strategies, data migration and integration plans, security and compliance processes, testing and rollback procedures, total cost of ownership and timeline, and the availability of post‑migration support.

SoftPro is the featured international partner leading this list and serves buyers in France and across the region. Evaluate each vendor on project methodology, platform expertise, delivery guarantees, and post‑launch support to align modernization risk and business objectives.

1. SoftPro

SoftPro is the featured international partner on this Top 15 list for readers seeking legacy system modernization in France. The company undertakes enterprise and mid-market modernization projects, large migrations, and SaaS transformations while delivering services remotely to clients across France from its European headquarters.

Technical strengths include hands-on experience with and .NET Core, cloud-native development on Microsoft Azure, and practical experience with enterprise CMS migrations including Umbraco. SoftPro pairs full-stack frontend and backend teams with dedicated project managers, quality assurance resources, and ongoing support to take legacy modernization projects from discovery through post-migration maintenance.

Key Highlights

• AWS support for cloud migrations and infrastructure.
• Frontend stack expertise in React and for modern web application rebuilds.
• Case studies that include business portals, CRM/HRM systems, SAAS ETL platforms, and social networks.
• More than 20 years of combined team experience across projects and industries.

Services

• Software development
• Web application development
• Cloud development
• Artificial intelligence

Contact Information

Website: soft-pro.pl

Phone: +48 571 282 759

Address: Poland, Warsaw, Mazowieckie Voivodeship, 13 Erasmus Ciołka St. 401

LinkedIn: www.linkedin.com/in/kyrylo-o

2. Capgemini

Capgemini is a global technology and consulting group that modernizes legacy systems by combining cloud migration, application replatforming, and data‑driven refactoring. The firm aligns cloud, data, AI, and systems engineering capabilities to reduce technical debt and enable more modular, observable application landscapes.

In France the company pairs strategic design from Capgemini Invent with systems and embedded engineering from Capgemini Engineering to modernize enterprise applications and product lifecycle platforms. This blended delivery model supports migrations, replatforming, and modernization programs that span both IT estates and product development environments.

Key Highlights

• Delivered a PLM modernization for Renault Group to strengthen data coherence and establish a digital foundation for future vehicle and process evolution.
• Designated as an SAP Sovereign Cloud Partner and noted on the site as the first partner to obtain that distinction.
• The site highlights the Capgemini Research Institute as being ranked number one six times.
• Identified on the site as an Official Technology Partner of the Tour de France and co‑launched the AI-powered fan experience “Dans Ma Course.”

Services

• Cloud
• Data & AI
• Cybersecurity
• Enterprise management

Contact Information

Website: www.capgemini.com

Phone: +33 1 57 99 00 00

Address: Capgemini Service, Place de l’Étoile, 11 rue de Tilsitt, 75017 Paris, France

Address: Capgemini – Capgemini Engineering – Capgemini Invent – Sogeti, 147 quai du Président Roosevelt, 92130 Issy Les Moulineaux, France

LinkedIn: linkedin.com/company/capgemini/

3. Atos

Atos modernizes mission‑critical legacy landscapes for large enterprises by refactoring monolithic applications into hybrid cloud architectures, introducing microservices patterns, and automating data and code migration. The company emphasizes risk‑controlled delivery using AI‑enabled development and testing frameworks alongside cloud orchestration to accelerate migrations without disrupting operations.

Atos combines on‑premise runbooks and managed hosting with cloud integration to replace aging stacks while preserving business continuity. Its approach targets large regulated and heavily operational environments where predictable, phased modernization and measurable reductions in technical debt are required.

Key Highlights

• Named ISG Provider Lens Leader for Mainframes in Europe in 2025 across four categories, including application modernization and MFaaS.
• Holds the AWS Mainframe Migration Competency, a formal recognition of its capability to migrate mainframe applications to AWS (announced 2021).
• Operates the Atos OneCloud program that provides multi‑cloud orchestration, cloud migration tooling, and modernization services (launched 2020).
• Reports a global applications practice of more than 21,000 application services experts supporting refactoring, low‑code platforms, and microservices implementations.

Services

• Mainframe modernization & cloud integration
• Mainframe-as-a-Service (MFaaS)
• Application modernization and refactoring
• Cloud and infrastructure modernization

Contact Information

Website: atos.net

Phone: +33 1 73 26 00 00

Email: globalprteam@atos.net

Address: River Ouest, 80 quai Voltaire, 95870 Bezons, France

LinkedIn: linkedin.com/company/atos

4. Sopra Steria

Sopra Steria is a European IT services and consulting group that delivers systems integration, software engineering, and transformation programs from its Paris headquarters and offices across multiple countries. The firm combines sector-focused delivery teams with an industrialised operating model to execute large-scale IT change programs.

For legacy system modernization, Sopra Steria aligns cloud and integration engineering with industrial tooling and domain teams to migrate, replatform, or refactor aging application estates and connect them to modern digital platforms.

Key Highlights

• The SAM (Smart Application Modernisation) methodology is a named, group-level approach Sopra Steria uses for structured legacy application transformation.
• A Cloud Center of Excellence supports application discovery & optimisation, containerisation, and mainframe modernisation delivery paths.
• Sopra Steria lists strategic partnerships with hyperscalers and technology providers including AWS, Google Cloud, Microsoft, IBM, Oracle, OVHcloud, GitLab, Salesforce and VMware.
• The company was positioned in the SPARK Matrix for Application Transformation Services 2022 and recognised as a Star Performer by Everest Group for application transformation.

Services

• Apps Modernisation
• Mainframe Modernisation
• Application Containerisation
• API & Integration Modernisation

Contact Information

Website: www.soprasteria.com

Phone: +33 (0)1 40 67 29 29

Email: contact-corp@soprasteria.com

Address: 4-6-6 Av de Kléber et 1-3 rue Lauriston, 75116 Paris, France

LinkedIn: linkedin.com/company/soprasteria

5. Orange Business Services

Orange Business is the enterprise division of Orange described on its site as an operator, integrator and platform player that combines network engineering and systems integration for large organizations. Its positioning aligns network, platform and integration capabilities to support complex IT transitions at scale.

The company pairs consulting-led transformation with migration and replatforming approaches that target hybrid cloud and modern platforms. Its site highlights a focus on data and AI alongside infrastructure engineering to modernize legacy applications and operational stacks.

Key Highlights

• Operates in 65 countries with teams present on all continents.
• Serves more than 30,000 B2B clients worldwide.
• Employs over 5,500 experts dedicated to AI, Data and Cloud.
• Maintains six Major Service Centers distributed across continents.

Services

• Cloud
• Data, IA & IoT
• Conseil & Transformation

Contact Information

Website: www.orange-business.com

6. Inetum (ex-GFI)

Inetum is a European digital services group that modernizes legacy enterprise systems by combining platform integration, industrialized delivery centers, and large-scale digital engineering to refactor and migrate business-critical applications.

The company uses rapid-prototyping FabLabs and a proprietary Coborg™ methodology to introduce AI-driven automation into migration roadmaps and accelerate safe production rollouts.

Key Highlights

• 26,000 consultants and specialists worldwide.
• Reported group revenue of 2.2 billion euros in 2025.
• Operates in 19 countries with industrialized nearshore and offshore delivery centers.
• Awarded an EcoVadis Gold Medal and has an SBTi‑validated decarbonization roadmap.

Services

• Application Services
• Cloud Modernization
• Data & AI
• Cybersecurity

Contact Information

Website: www.inetum.com

Address: 5-7 rue Touzet Gaillard, 93400 Saint-Ouen, France. (inetum.com)

Phone: 33(0)144045000. (inetum.com)

7. Wavestone

Wavestone helps large organizations modernize legacy applications and migrate them to cloud‑native platforms to reduce technical debt and improve performance. The firm works with CIOs and CTOs to design migration roadmaps, perform technical and security assessments, and sequence migrations to limit downtime.

Delivery emphasizes detailed application assessments, move‑group migration sequencing, and security‑by‑design checks to replatform, refactor, or retire legacy assets. Wavestone also publishes practical cloud migration guidance and operational stages to standardize execution across large application portfolios.

Key Highlights

• In a banking engagement, Wavestone applied an AI‑enabled migration approach that achieved over 70% migration accuracy across initial use cases and saved up to eight hours of manual work per migration.
• For a global insurer migration, Wavestone redesigned and migrated more than 120 applications while leveraging Azure Key Vault and Log Analytics to ensure secure cloud operations.
• Wavestone led an ERP modernization for PE Automotive that implemented Microsoft Dynamics 365 for roughly 120 active users across multiple entities.

Services

• AI-assisted application migration
• Mainframe integration and modernization
• ERP transformation (Microsoft Dynamics 365)

Contact Information

Website: www.wavestone.com

Phone: +33 1 49 03 20 00

Phone: +33 1 49 03 27 26

Address: Tour Franklin, 100-101 terrasse Boieldieu, 92042 Paris La Défense CEDEX

8. Zenika

Zenika is a French IT consultancy that brings cloud engineering, architecture, and DevOps together to modernize legacy systems for enterprise clients. The firm emphasizes containerization, serverless patterns, and automated CI/CD pipelines to replace monolithic applications with scalable, observable services.

Delivery mixes on-the-ground delivery teams with acculturation programs to train client engineers while migrating systems. This combination of hands-on delivery and formal training supports large modernization programs that require both replatforming and skills transfer.

Key Highlights

• Achieved the Application Development Specialization in the Google Cloud Partner Advantage Program.
• Operates a public training platform and publishes downloadable course materials for practitioner-level upskilling.
• Publishes migration case studies that document moves to Google Kubernetes Engine and use of Pub/Sub and Firestore in production projects.
• Headquartered in Paris with multiple French agencies and international offices listed on the company site.

Services

• Cloud Migration
• Architecture Modernization
• DevOps & CI/CD
• Training & Coaching

Contact Information

Website: www.zenika.com

Phone: +33 (0)1 45 26 19 15

Address: 53 rue de Châteaudun - 75009 Paris

LinkedIn: linkedin.com/company/zenika/?originalSubdomain=fr

9. Zenika (duplicate)

Zenika is a French consulting and engineering firm that modernizes legacy systems by migrating applications to cloud-native architectures, containerizing JVM-based backends, and building CI/CD pipelines and cloud infrastructure. The firm applies practical DevOps and software craftsmanship practices while pairing technical delivery with organizational coaching to reduce migration risk.

Zenika combines on-the-ground delivery teams with developer upskilling and structured training programs to accelerate modernization projects and help clients maintain modern platforms over time.

Key Highlights

• Premier Google Cloud partner with 60+ Google Cloud certifications across its teams.
• AWS Consulting Service Partner supporting migrations, serverless patterns, and container workloads.
• More than 47,000 open-source contributions across over 7,000 projects, demonstrating sustained community engineering activity.
• Zenika Academy and training programs have upskilled about 30,000 people since the company’s founding.

Services

• Cloud Migration
• Containerization
• CI/CD & DevOps
• Training & Upskilling

Contact Information

Website: www.zenika.com

Phone: +33 (0)1 45 26 19 15

Email: training@zenika.com

Address: 53 rue de Châteaudun, 75009 Paris, France

LinkedIn: linkedin.com/company/zenika/?originalSubdomain=fr

10. Capgemini Engineering

Capgemini Engineering consolidates Capgemini’s global engineering and R&D capabilities into a single brand that designs, develops, and deploys technologies at the intersection of physical products and digital software. The practice combines product and systems engineering with scaled delivery networks to translate complex technical architectures into operational solutions.

That combination makes Capgemini Engineering a logical fit for legacy system modernization where convergence between hardware, embedded software, and enterprise platforms is required. Its focus on engineering continuity across the product lifecycle supports incremental modernization paths that preserve operational integrity while updating software and system architectures.

Key Highlights

• Launched as a consolidated Capgemini brand on April 8, 2021, following the integration of Altran.
• Zinnov placed Capgemini’s global ER&D services in its Leadership Zone in January 2021.
• Official materials state more than 52,000 engineers and scientists operating across over 30 countries.
• Official sector coverage lists aerospace, automotive, rail, energy, life sciences, telecoms and semiconductors.

Services

• Digital Engineering
• Software Product Engineering
• Augmented Engineering (Gen-AI)
• Cloud

Contact Information

Website: www.capgemini.com

Email: engineering@capgemini.com

Address: Altran Technology & Engineering Center SAS, 4 avenue Didier Daurat, 31700 Blagnac, France

11. SQLI

SQLI is a European digital services group that modernizes business-critical legacy systems and builds commerce and enterprise platforms. The company delivers end-to-end projects from strategy and design through engineering-led delivery, using sprint-based teams to implement cloud-native replatforms and gradual migrations.

Its delivery model emphasises code refactoring and incremental replatforming while preserving operational continuity to reduce technical debt. That engineering-led approach and experience with complex commerce and public-sector platforms make SQLI a fit for legacy system modernization in France.

Key Highlights

• Holds Adobe Gold Solution Partner status and Magento Commerce Specialisation.
• Operates six offices in France and lists 900 digital specialists on its France pages.
• Publishes case studies of legacy-modernisation projects for clients including Tesco Mobile, Sharp Electronics Europe, and the État de Vaud public sector.
• Provides API integration frameworks designed to connect legacy systems with cloud and SaaS platforms for real-time data flow and reduced bottlenecks.

Services

• Experience Platform
• Data & AI
• Application Engineering
• Digital Continuity

Contact Information

Website: www.sqli.com

Phone: +33 (0)1 85 64 20 20

Email: contact@sqli.com

Address: Immeuble Maslo 2-10, rue Thierry Le Luron 92300 Levallois-Perret France

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12. Smile

Smile is a European open-source IT services group that delivers digital experience, e‑commerce, business applications, embedded & IoT, cloud, and data & AI solutions. The firm aligns enterprise architecture and applications engineering with modern delivery practices to support migrations and application renewal for legacy business systems.

Smile operates an augmented Factory accelerated by agentic AI to speed delivery and promote digital autonomy for client teams. The group counts more than 2,000 professionals across France and Europe and maintains local agencies to work directly with customers during modernization projects.

Key Highlights

• Operates 11 agencies across France and maintains a broader European footprint.
• Client references on the site include Somfy, UNESCO, Azelis, and Snowleader.
• Paris office reports 350 projects deployed, a 10‑year average collaboration time with clients, and 32 years of experience.
• Publishes practical resources such as the "37° Digital Maturity Scan" and a guide titled "Using Linux as a Real Time Operating System" for Embedded & IoT.

Services

• Agentic Commerce
• B2B portal
• Customer engagement & CRO
• Data & AI Platform & Integration

Contact Information

Website: www.smile.eu

Phone: +33 1 41 40 11 00

Address: 163 quai du Dr Dervaux, 92600 Asnières-sur-Seine, France

13. Neurones

Neurones is a French consulting and digital services group that helps organizations modernize legacy IT by combining infrastructure modernization with application renewal and targeted AI integration. The company runs modernization programs through specialized delivery entities that focus on high availability, secure access and progressive migration paths to renew systems while accelerating AI adoption.

Key Highlights

• 7,500 experts across the group, positioned among the leading digital services firms in France.
• Infrastructure services pole staffed by approximately 5,400 people focused on availability, secure access, management and evolution of IT estates.
• Application services pole with about 1,600 collaborators and thirty years of experience in application projects and system improvements.
• Publicly listed on Euronext under the ticker NRO.

Services

• Infrastructure services
• Application services
• Consulting

Contact Information

Website: www.neurones.net

Phone: 01 41 37 41 37

Address: Immeuble "Le Clemenceau 1", 205, avenue Georges Clemenceau, 92024 Nanterre cedex

14. Sopra Banking Software

Sopra Banking Software builds modular, API-first banking technology that helps banks replace legacy cores through phased, low-risk modernization programs. The company pairs a composable digital stack with integration and run services to migrate front, middle, and back-office functions while preserving existing operations during transition.

Its delivery model emphasizes cloud-ready deployments, middleware-led integration, and a marketplace of components so clients can modernize incrementally and expose capabilities to partners and fintechs. This combination of composability, an API layer, and operational services positions the firm for legacy system modernization projects in France and other markets.

Key Highlights

• 280+ customers use SBS Core Banking products, listed on the site as Amplitude, SAB and Thaler.
• The company cites a catalog of 400+ banking APIs and a market-leading API platform for ecosystem integration.
• Official materials state solutions run on AWS, leverage Axway premium API capabilities, and support middleware on OpenShift.
• Sopra Banking reports executing more than 50 core banking system upgrades per year to support progressive modernization.

Services

• Amplitude (core banking)
• SBS Digital Banking Suite
• Ecosystem Engagement
• Composable Banking Service Store

Contact Information

Website: www.soprabanking.com

Phone: +33 4 50 33 30 30

Address: Tour Trinity, 1bis Place de la Défense, 92400 Courbevoie, France

LinkedIn: linkedin.com/company/s-b-s/

15. Micropole

Micropole is a French data and digital consulting firm that modernizes legacy IT landscapes by aligning data strategy with migration planning, system integration, and cloud acceleration.

The firm operates a consulting-to-implementation delivery model that combines data governance, migration execution, and platform rationalization to consolidate and modernize legacy systems.

Key Highlights

• Integrated into the Talan group in May 2024, with Micropole content and teams consolidated on.
• Maintains a broad partner ecosystem that includes TIBCO EBX, Semarchy, MuleSoft, Talend, Oracle Hyperion, Pigment, Board, Power BI, Tableau, Qlik, Snowflake, and Databricks.
• Becoming part of Talan gives access to roughly 6,000 consultants across five continents for large-scale modernization programs.
• Operates centres of excellence in Tunisia, Mauritius and Hungary to support offshore delivery and scaling of modernization work.

Services

• Master Data Management
• Systems Integration
• Cloud Acceleration
• Data & AI Strategy

Contact Information

Website: www.micropole.com

Phone: +33 (0)1 74 18 74 18. (suisse.micropole.com)

Address: 91/95 rue Carnot, 92300 Levallois-Perret, France. (suisse.micropole.com)

LinkedIn: linkedin.com/company/micropole/ (linkedin.com)

Conclusion

SoftPro is the featured partner on this Top 15 list for readers seeking legacy system modernization in France. To choose a provider, match vendor scale and delivery model to your project scope and timeline, and prioritize demonstrable experience with your regulatory and technical constraints.

Also weigh whether you need stronger data strategy, network integration, open-source alignment, or banking-specific composable approaches, and balance local presence and delivery-center models against cost and vendor risk. Request client references, a migration roadmap with rollback options, and a proof of concept before committing.