CUT Architectures founders Benjamin Clarens and Yann Martin added the 16-square-metre extension to one side a 1920s house in the Parisian suburb of Chaville.
Following their previous extension to the property, which provided a music room and a garage, this second addition forms a new entrance, stairwell and study. They named the project House Extension for a Cellist Part II.
Like the first extension, the new structure is squeezed between the walls of the existing house and a neighbouring property.
"The construction is a concrete volume inserted between the western facade of the existing house and the neighbour's house, offering an entrance and a desk to the whole house," explained Clarens and Martin.
The base of the extension is clad in sheets of aluminium mesh and aligned with the facade of the existing house, while the glazed upper storey is surrounded by a concrete frame and set back in line with the facade of the neighbouring building.
"A concrete frame echoes the previous project and the painted frames of the windows of the existing house above the expanded aluminium panels," added the architects.
The anodised aluminium panels, which match the garage shutters, conceal the glazed entrance.
Inside, a floating staircase with bright yellow treads and a banister leads to a study that overlooks the green roof of the lower storey.
A steel sheet intersects the lacquered banister to provide a desk set against the glazing.
"The desk as well as the staircase is conceived as a continuous yellow lacquered steel structure suspended above the concrete slab and staircase," said the architects.
Photography is by David Foessel.