A group home, essentially an orphanage for teenagers, may not have been Damien Brambilla’s dream commission. The budget was tight, the bureaucracy heavy, the room to design something radical—or even just artful—more or less nonexistent. But where others would see a headache, Brambilla, a Paris-based architect, saw an opportunity to change what this type of building can mean to its occupants—in this case, a dozen adolescents under the care of the city government. Some had lost both parents; some had been removed from parental care by the state. Brambilla explains that he wanted them to feel “chez soi,” at home, returned somehow to “the house they no longer have or one they never even knew.”

He took a derelict apartment building with an overgrown garden in the Belleville section of northeastern Paris, gutted it to the foundation, and added an extension that doubled the original square footage. On the street side, he restored the typically Parisian facade, but indoors it’s a different world, all glass, lacquered metal, and sleek wood. Brambilla’s reference point was not French—much less Parisian—but rather Californian: the revolutionary midcentury Case Study Houses, which emphasized structural lightness and a breezy continuity between indoors and out.

The project, completed early last year, was not without its challenges. The narrow lot, accessible via a tiny, sloping street, offers little room to bring in heavy materials. “We needed to use easily transportable equipment and a minimum of concrete, reserving it for the foundations and the construction of the flooring,” Brambilla says. But he enjoyed luxuries not usually available for such projects, including a generous budget (2.6 million euros, or $2.9 million), furnished by the French government, that allowed him to acquire quality furniture, including Hay chairs and Abstracta desks.

At 250 square feet, the shared bedrooms are smart and airy, despite their small size. But Brambilla tried to create spaces that would encourage common living: from a long kitchen bar, where residents can eat and socialize, to a covered terrace and a peaceful garden, filled with shade-loving varietals that bloom year-round. That “jardin romantique,” designed by the Paris-based landscape architecture firm Atelier Roberta, is both the “heart and the lungs” of the house, Brambilla says.

In drawing up the plans, the architect consciously included a safe outdoor space as an antidote to the potentially claustrophobic dormitory rooms. “I’m maybe a bit naive to think that this garden and the sensitive interior space will have the capacity to soften the sometimes difficult daily lives of the adolescents that live here,” says Brambilla, “but that was nevertheless my underlying intention.”