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Modernizing an HRIS is about much more than changing software. It means rethinking HR processes, harmonizing practices internationally, and creating the conditions for a consistent employee experience, regardless of the country or site.
This was the challenge Mersen took on between 2022 and 2023 with the Themis project: replacing an aging HRIS with SAP SuccessFactors, leveraging Arago's expertise to cover the entire HR landscape, from Core HR to talent management, including recruitment and compensation.
This case study, told by Jean-Baptiste de Clermont-Tonnerre, Mersen Group's HRIS Manager, illustrates the reality of a large-scale international HRIS project: the strategic choices, adjustments made along the way, and lasting lessons learned.
Mersen is in a specific position: it is a mid-sized group, but with a strong international presence.
“Back in 2010, our senior management identified the need for a global HRIS, primarily to gain a clear view of our workforce across the world, but also to effectively deploy key processes, particularly those related to employee performance and compensation,” explains Jean-Baptiste de Clermont-Tonnerre, Mersen Group's HRIS Manager.
Thanks to this tool, the Human Resources department was able to strengthen its HR culture and processes for nearly twelve years.
“Over the years, our HR processes became more sophisticated, to the point where our HRIS was starting to show its limitations. Despite its strengths, it could no longer meet the new ambitions of our 2021–2025 HR roadmap, which was built around three main pillars: strengthening Mersen's identity; making Mersen a learning organisation; and enhancing the employee experience. We therefore needed to adopt a new HRIS offering broader functional coverage. A rich, modern and user-friendly solution, but also a more accessible one, so that all our employees, including those working on the factory floor, could access it directly.”
Mersen is a global expert in electrical specialties and advanced materials, with products serving industries as diverse as wind power, solar energy, aerospace, electronics, and electric mobility. The Group employs more than 7,500 people across 33 countries, with 21 R&D centres and over 50 industrial sites worldwide. In 2024, its revenue reached a record €1.244 billion, with 55% generated from sustainable development markets.
Managing human resources at this scale requires an HRIS capable of consolidating workforce data across highly diverse environments, deploying consistent HR processes such as performance management, compensation, and mobility while adapting to local regulations, and providing an experience simple enough to be adopted by employees working both in offices and on the factory floor.
Mersen had been using a global HRIS since 2010, long before SaaS solutions came to dominate the market. For more than a decade, the system helped structure the Group's HR practices and supported the deployment of its key processes.
However, the ambitions of the 2021–2025 HR roadmap highlighted its limitations. Built around three pillars — strengthening the Mersen identity, becoming a learning organisation, and enhancing the employee experience — the roadmap required broader functional coverage, a more modern user experience, and greater accessibility for all employees, including those working on the factory floor.
Faced with these challenges, Mersen launched a structured tender process involving the leading players in the HRIS market. The decision was not based solely on functionality. Jean-Baptiste de Clermont-Tonnerre explains: “Today's solutions offer far fewer customisation options, and standardisation is often the norm. We were therefore concerned about facing a certain level of rigidity and finding it difficult to adapt the tool to our specific needs.”
This is precisely where Arago made the difference. By demonstrating its ability to implement SAP SuccessFactors in close alignment with Mersen's processes, without compromising the standardisation required for an international deployment, Arago secured the project.
SAP SuccessFactors is now used by nearly 9,900 customers worldwide. Its strength lies in its ability to support the entire employee lifecycle, from recruitment and performance management to compensation, learning, and succession planning, while adapting to the legal requirements of each country.
For a group like Mersen, this comprehensive functional coverage, combined with a SaaS architecture updated twice a year, provided the scalability and flexibility that the previous system could no longer offer.
The Themis project began at the end of March 2022. Rather than opting for a big-bang approach, the project team chose a gradual, phased deployment, making it possible to deliver initial value quickly while ensuring teams could manage the workload.
This phased approach enabled Mersen to reduce the risks associated with launching the entire scope simultaneously while gradually involving the business teams. “Starting with a mini Core HR allowed us to activate an initial module, Performance, quickly, while extending the timeline for the rest of the project to adapt to our teams' workload. Arago demonstrated real agility throughout this process.”
The functional scope covered by Mersen's SAP SuccessFactors HRIS is now significant.
| SAP SuccessFactors module | Main use |
|---|---|
| Employee Central | Core HR: employee data, positions, and global organisational structure. |
| Performance & Goals | Annual performance reviews, goal management, and evaluations. |
| Recruiting | Job posting, application tracking, and candidate selection. |
| Onboarding | New employee onboarding and administrative procedures. |
| Compensation | Compensation management and salary review cycles. |
| Succession & Development | Succession planning and strategic talent management. |
| Cornerstone integration | Connection with the Group's LMS for learning and training management. |
Every large-scale HRIS project goes through moments when business processes do not immediately align with the solution's standard capabilities. Jean-Baptiste de Clermont-Tonnerre describes this reality candidly: “At times, we had to adapt our processes to fit the tool. However, whenever we encountered challenges that seemed impossible to solve, Arago rolled up its sleeves to find the best possible compromise. It was through working together, as partners, that we were able to find solutions.”
It is precisely in these moments that the quality of an implementation partner becomes clear. Deep product knowledge, the ability to understand client priorities, and agility in managing trade-offs can make the difference between a project that moves forward and one that becomes stuck.
Today, Mersen's HRIS is in Run mode, with application maintenance (AMS) provided by Arago. HR campaigns are now managed through a single, consistent solution accessible to all employees across the Group, including those who previously had limited access to digital tools.
After each campaign, feedback from business teams is systematically collected: what worked, what was missing, and what needs to evolve. The solution is then adjusted accordingly. This continuous improvement process, built into the project from the design phase, is one of the key factors ensuring long-term adoption.
Jean-Baptiste de Clermont-Tonnerre also highlights an often-overlooked organisational benefit: “For us, this project was an opportunity to adapt and modernise some of our HR processes. It also helped us improve our organisation, particularly by establishing a process for collecting requirements and identifying BPOs, whose role was instrumental throughout the project.”
The Mersen project took approximately 18 months, from its launch in March 2022 to the full deployment of the Recruiting module at the end of 2023. This timeframe is representative of an international, multi-module deployment involving data migration. A more limited scope can be completed within 6 to 12 months. The phased approach adopted for the Themis project is often recommended to reduce risk and support user adoption.
Data migration is one of the most critical phases of an HRIS project. It involves a preliminary audit of the quality of existing data, mapping it to the new data model, and carrying out extensive testing before go-live. At Mersen, migration to the final Core HR was completed in July 2023, alongside payroll integration, requiring close coordination between the IT, HR, and Arago teams.
SAP SuccessFactors includes localizations for most of the countries where Mersen operates, covering local contract management, regulatory compliance, and interface languages. The challenge is finding the right balance between standardisation, which ensures data consistency across the Group, and local flexibility, which supports adoption in the field. Arago supports its clients in defining this balance, drawing on its experience across more than 1,000 international projects.
Application maintenance (AMS) refers to the support and enhancement contract entrusted to an external service provider after go-live. It covers bug fixes, adjustments related to new SAP releases (twice a year), and functional enhancements requested by HR teams. Arago provides AMS for Mersen's HRIS, ensuring service continuity and in-depth knowledge of the client's specific configuration.
Business involvement in the Themis project centred on identifying BPOs (Business Process Owners) within Mersen's HR teams, with designated business representatives for each functional area. Their role was crucial: they brought field requirements to the project, validated configurations, and facilitated user adoption. This governance model is now recommended by Arago for all its large-scale HRIS projects.
Business involvement in the Themis project centred on identifying BPOs (Business Process Owners) within Mersen's HR teams, with designated business representatives for each functional area. Their role was crucial: they brought field requirements to the project, validated configurations, and facilitated user adoption. This governance model is now recommended by Arago for all its large-scale HRIS projects.
