The densely populated highrises on the outskirts of Paris might lack the charm of the older residences in the city centre, with their carefully proscribed heights and quaint cast-iron balconies. Yet the handsome Day Care and Young Workers’ Hostel, which sits at the edge of the 20th arrondissement in close proximity to Les Lilas, a suburb lying just across the city boundary, takes its cues from old and new. Design team of Chartier Dalix Architectes and Avenier Cornejo Architectes sought to stitch together the disparate communities within this rapidly gentrifying district by picking and choosing materials and forms that would resonate with neighbours on both sides.

Commissioned by Paris rental housing agency RIVP, the project combines three functions within a single monolith: a hostel for immigrants, another for young workers, and a 66-place day care. At 10 storeys, the shape of the structure hews to the height of the traditional Parisian housing block, but is clad in grey brick to correspond to the low-cost housing blocks around it; these bricks are hand-made to create a variety of light and dark tones with a “velvety” texture.

Instead of sheltering an interior courtyard, the block is cleaved by a horizontal rift of glass-fronted balconies that encircle the structure on the fourth floor, as well as a vertical rift that rises from the second storey to the ninth. Lined with copper sheeting, these fissures introduce a warm, inviting tone that contrasts with the mottled grey of the surrounding brick. The fourth floor and its balconies are entirely turned over to the hostel’s common areas – including a media centre, sport hall and group kitchen – designed to let the residents mingle. The vertical chasm similarly channels light deeper into the building, and enhances the link between the facade and the street below. Setbacks of the eighth, ninth and tenth floors create spaces for additional narrow terraces, finished in aluminum.

The apartment interiors are, at 18 square metres, compact in true Parisian form, with an open plan to allow for the maximization of all available space. The kitchenette can be hidden behind shutters when not in use, and the other furnishings, including benches, tables with drawers, and trundle or pull-out beds, are custom designed by the architects with elegantly spartan lines. All the flats benefit from copious daylight courtesy of windows averaging four square metres in size.

This kind of reliance on passive energy, supplemented with renewable energy sources, has been deployed throughout the building. The daycare, on the ground floor, opens onto an enclosed play area under a mesh that provides a reduction in glare while still admitting plenty of sunshine. On the rooftop, two wind turbines provide the energy for the daycare and the hostels’ common areas, while solar panels supply a further 30 per cent of the total energy used.