Cachan, France
Under studies

“Reversible” Eco-district

For the project for a new district developed around Cachan railway station, systematic and exhaustive research was carried out into the technical and architectural methods that would enable achievement of maximum-level performance in environmental terms: a positive-energy, low-carbon district (buildings E3 C2 and E4 C2).
BNP Paribas Real Estate
SPIE Batignolles Immobilier
New mixed-use complex around the future Arcueil-Cachan station (part of the Grand Paris Express transit network) including residential area, offices, retail, services, hotel.
Under studies
30 500 m²
Bâtiment biosourcé – Niveau 2
E+/C- (Niveau énergie 4 et Carbone 2)
NF Habitat HQE – Excellent
NF Bâtiment durable – Excellent
BREEAM Excellent (commerces)
Numerous methods were employed in designing a positive-energy district:
- The south façades of the Station block and the roof of the Central block were covered with photovoltaic panels, ensuring effective solar protection while forming an integral part of the building’s architecture.
- High thermal performance of the envelopes (glazing ratio > 40%, natural ventilation, solar protection)
- Use of passive systems (ground-coupled heat exchangers, connection to local network for all the buildings)
- Choice of low-carbon and bio-sourced materials (wood for façades, frameworks and carpentry; raw earth for some construction components; low-carbon concrete for the ground floors; wood wool or recycled materials for insulation)

Assessment of the reversibility of the buildings was also a key issue in the project design, with a view to ensuring the buildings’ durability and anticipating societal changes. The layouts and heights of floor tiles in the office spaces were designed to enable conversion to living accommodation that would be both comfortable and compliant with technical standards. A column and beam system, light façades and adaptation of the vertical circulation all make the buildings easier to disassemble.

A district that incorporates and protects nature. Transition management also takes account of the place of plant life in the project. Private and shared gardens, terraces, planted roofs and a hop field have all been added to the vegetal landscape of the public spaces (streets and squares edged with trees, planted pits, open ground spaces). This extended landscape layout helps make the town more porous and helps combat urban heat islands.

Mechanisms for rainwater recovery and management were incorporated into the project with the inclusion of humid zones, installation of recovery tanks for watering green spaces and maintaining shared parts, and installation of water-efficient facilities in the residential buildings.

A district that ensures a healthy and convivial living environment

Unique in its relationship with the station, the Cachan eco-district was designed as a coherent urban ensemble, alive, peaceful, conducive to being neighbourly – chatting, getting together, sharing activities – and providing a healthy, comfortable living environment for its residents. The convenient homes, the facilities and the layouts all contribute to ease of mobility.

This new district was an opportunity to lay the foundations for a mixed-purpose, equitable district that encourages social bonds, inclusion and community spirit.
Monaco Offshore Extension