Introduction

The transformation of the former Nanterre office buildings into a 646-room residence marks a significant shift in urban regeneration strategies. The project, led by ADIM Paris Île-de-France and acquired by in'li, has been awarded Effinature certification. This is a crucial achievement: it demonstrates how a high-density redevelopment project can integrate ecological performance without altering the existing structure.

Major requalification: the conditions for credible environmental certification

The main challenge of this type of project lies in converting an office building into a complex of housing and research spaces. Effinature certification serves here as a framework for maintaining ecological requirements within a constrained context.

• fixed structures and non-modifiable load-bearing grids; 
• large mineral surfaces; 
• initial absence of vegetation continuity; 
• constraints of multiple uses (housing, coworking, catering, sports, collective living).

Methodological interest: Effinature is not limited to verifying the presence of vegetation. It requires a functional analysis of nature in the city (soils, infiltration, species, coexistence) and independent verification of the results.

5,000 m² of green space: a tool, not an argument

According to the press release, the project includes:

• 5,000 m² of green spaces;
• 63 trees adapted to the climate of the Île-de-France region;
• flowerbeds, terraces and green roofs; 
• a pedestrian route in a green environment; 
• permeabilized surfaces improving infiltration.

In the Effinature framework, these elements are interpreted through six themes:

1. Preserving living soil: limiting artificialization, removing impermeable surfaces from parking spaces, restoring the ecological quality of soils...
2. Development of plant heritage: floristic diversity, ecological continuity, rainwater management through living organisms, preservation of tree heritage...
3. Support for local wildlife: elimination of mirror effect, sealing of trap cavities, creation and maintenance of habitats, adaptation of the work schedule...
4. Reducing the project's impacts: controlling noise and light pollution, waste management, wood quality, environmental monitoring of the construction site...
5. User well-being: visual comfort, stimulation of the five senses, strengthening of social bonds, educational pathways, awareness-raising...
6. Skills development: qualification and commitment of project teams in the design and implementation phases...

This framework avoids the pitfall of mere “greening”, by requiring proof of ecological effectiveness.

Urban heat islands: a measurable demonstration

The Effinature approach places great importance on reducing temperatures during the summer months. The 63 trees and vegetated areas aim for two effects:

• shading and reduction of average temperature; 
• evapotranspiration allowing for local cooling.

The project illustrates the convergence between ecological certification and urban climate adaptation.

Urban recycling + certification: a new trajectory

The redevelopment of vacant offices is often viewed from the perspective of housing and land conservation. The example of Nanterre shows that a shared residential and scientific space can meet the requirements of independent certification, even within a rigid building framework.

This approach opens a path for future operations in the Île-de-France region:

• limit the use of demolition; 
• maintain measurable ecological performance; 
• rehabilitate without reducing environmental ambition.

Conclusion

The Cité Internationale de la Recherche in Nanterre demonstrates that Effinature certification can be applied to major redevelopment projects in dense and constrained urban environments. The project illustrates a possible trajectory for areas facing housing pressures:

• recycle what already exists; 
• restore measurable ecological functions; 
• to organize the coexistence between human uses and natural dynamics.

This is a reference case for understanding how functional nature can structure an urban transformation project.