Situated at the southern edge of the Baud-Chardonnet mixed-use development zone (ZAC) in Rennes, the ILOT O2 project contributes to the city’s eastward urban expansion. Thanks to its highly strategic location—bordered by the Vilaine River to the north and railway tracks to the south—the site benefits from a unique urban character and strong landscape identity.
The Vilaine’s recently redeveloped banks offer recreational opportunities for both leisure and sport. Adjacent to the river, a landscaped park has become a central element of the future neighborhood, acting as a key amenity for residents and a focal point of the design. To the south, the railway lines—conceptualized as an “iron river”—form a contrasting yet complementary frame that echoes the rhythm of the Vilaine, enhancing the site’s visual coherence.
Designed as a contemporary urban fragment, the project emphasizes a harmonious mix of built form, public space, and social interaction. It fosters connectivity, spontaneous encounters, and shared well-being through a careful orchestration of programmatic diversity.
The site hosts three buildings co-designed by three architectural practices, integrating social and private housing with artisanal workshops, offices, and commercial spaces. Each building functions independently, supported by a centralized multi-level parking structure. A shared garden weaves the site together, with permeable green spaces that promote rainwater infiltration and biodiversity.
Architectural Strategy and Composition
Building B—the central block—posed significant design challenges, particularly in ensuring programmatic independence (residential, office, and retail) while maintaining regulatory compliance and spatial coherence. Its volumetric articulation allows each function to receive adequate daylight and space. The stepped office volumes descend westward, opening views toward Building A’s green spaces, while receding to the southeast to accommodate a taller central section that anchors the block. These terraces serve as informal outdoor workspaces and social areas for office users.
Residential volumes are offset to minimize direct visual connections with the offices. As the building rises, it aligns with the adjacent parking structure and offers open, unobstructed views over the surrounding landscape. This spatial rhythm accentuates the transitions between different programmatic blocks.
The project employs expressive circulation elements—vividly colored external staircases—for both residential and office uses. These vertical components animate the northern façade, connecting the volumes while offering a playful architectural gesture.
Materiality and Environmental Integration
The architectural language is intentionally rational and understated, drawing inspiration from the industrial aesthetic of nearby railway infrastructure. Office façades articulate a visible structural grid and large, loft-style openings. The residential tower features a clean, consistent pattern that reinforces the stepped massing.
Exterior spaces vary by level: lower levels feature open loggias, while upper floors incorporate enclosed winter gardens, providing year-round usability and protection from the wind. The roofscape breaks into four distinct volumes topped with shed roofs fitted with photovoltaic panels, contributing to energy self-sufficiency. These pitched roofs also introduce soft, diffused light into the top-floor apartments and avoid a heavy, monolithic crown, helping the tower blend with the skyline.
A key design principle was to ensure all elevations engage equally with their urban surroundings—there is no front or back façade. The project embraces a 360-degree orientation, fostering connections with the wider city.
Material choices have been deliberately limited to concrete, timber joinery, and metal railings, emphasizing their natural qualities. The residential tower’s lightly tinted concrete references the mineral tones of local schist and brick while subtly nodding to the railway vernacular.
