In a few years, a parking lot at the edge of Paris will turn into what architects call “a floating village in the middle of a forest”–a tree-covered building, topped with homes on the roof, that doubles as a pedestrian bridge over a nearby highway.

“You go up, you go through the forest, and you go to your small home and garden,” says Manal Rachdi, founder of Paris-based Oxo Architects, who partnered with Sou Fujimoto on the design. “You really have a normal house on top of the building. The only difference from a normal house–you have a view of the Eiffel Tower.” And you’re surrounded by 1,000 trees, in the middle of the city.

Sitting at the border of the 17th arrondissement, the building will span over the city’s ring road, a highway that separates the city center from the suburbs. “It physically creates a very big gap between Paris and the surroundings,” says Rachdi. “One of the challenges is to erase the gap created by this highway, and the first step is creating this park, with its trees. Everyone can go up and pass the highway through the park.”

The tree-filled pedestrian bridge is on one layer, and another layer is filled with small single-family homes and apartments. In between are offices, a daycare, and restaurants. The building slants downward, like an inverted pyramid, to maximize the amount of public space in the park at the bottom.

Rachdi and Fujimoto have designed tree-covered buildings in the past, like this high-rise apartment building in Montpellier, France. But they saw an even greater need for green space in Paris.

“One of the major ideas is how to invent a new way of living in Paris,” Rachdi says. “As you may know, Paris is a stone city–there’s not a lot of trees, not a lot of vegetation. We wanted to create this living space surrounded by nature … connected to the city, but surrounded by nature.”

Putting greenery on architecture might be becoming common, but it’s not a design gimmick. Trees help filter pollution, fight rising urban temperatures, and make people living nearby happier and even feel younger. And putting them on buildings has additional benefits.