Equilis, a green renaissance in the heart of Issy-les-Moulineaux

We have just completed the Equilis project in Issy-les-Moulineaux, a major 16,500 m² transformation that marks a new chapter both for the business district and for our practice. Originally designed more than twenty years ago by Anthony Bechu under the name Steris, the building is now reborn as Equilis, following an in‑depth renovation that weaves together architectural heritage, sustainable innovation and circular economy. With this project, we give enduring form to an intuition that was already pioneering at the time: an architecture able to evolve with the city, to reinvent itself rather than disappear, and to become a tangible vehicle for environmental transition.

Equilis is part of an unprecedented sustainability approach for the district, prioritising what already exists over demolition and reconstruction. We have preserved, transformed and re-used 165 tonnes of materials (marble reinterpreted as terrazzo, elements retained and upgraded), avoiding 53 tonnes of waste and achieving an estimated carbon saving of 237 tonnes of CO₂. Compared with a conventional renovation, the project cuts emissions by 15 to 35% and halves energy consumption, demonstrating that an existing office building can become exemplary without starting from scratch. This circular-economy mindset, combined with a rigorous selection of durable materials, is redefining the benchmarks for responsible office refurbishment.

Equilis belongs to this family of “phoenix” projects that rise again from their own foundations to write a new story, like ONE, now the Canal+ headquarters, or MONDO. We have completely reimagined the 16,500 m² to provide more flexible, brighter and more welcoming floorplates, capable of supporting the evolution of work organizations and collaborative practices. The entrance has been reinstated at street level, reconnecting the building to its neighbourhood and making the base more open, legible and hospitable for both occupants and local residents. Generous shared spaces, places for social interaction, features that encourage soft mobility and pooled services all contribute to making Equilis a living hub rather than a simple office building.

Beyond environmental performance, the project was conceived to place well-being and living nature at the heart of occupants’ daily experience. More than 600 m² of outdoor gardens, patios and planted terraces reintroduce greenery into the office fabric, fostering biodiversity and providing breathing spaces on every floor. Natural light, air quality, views onto landscaped areas and warm materials shape biophilic spaces designed to reduce fatigue, support users’ appropriation of the premises and enhance the site’s appeal. In parallel, cutting-edge technologies – intelligent building management systems (smart BMS), energy recovery, fine-grained consumption monitoring – ensure a high level of user comfort while keeping the energy footprint under control.

Equilis is also a collective endeavour and, in a special way, a family one. Bechu & Associés worked hand in hand with Volume ABC, the practice led by Aliénor Bechu, to orchestrate this transformation between continuity and reinvention. Together, we have made Equilis a powerful landmark for Issy-les-Moulineaux, proof that a building can be a resource, capable of being reborn, turning greener and opening more generously onto its neighbourhood. Through its environmental commitment, its ambitious certifications – BREEAM International Excellent, BBCA Rénovation, SmartScore, WiredScore Gold, Ready to OsmoZ – and its renewed urban presence, Equilis embodies a vision of the city that rebuilds itself from within, reduces its carbon footprint and restores life, well-being and nature to the foreground.