This 120sqm Haussmanian apartment for a family of three children is organized around three main elements. The entrance with two vertical mirror surfaces marking the threshold between the reception and the private spaces. A crossing space bringing together the kitchen, the dining room and the living room designed so that the programs mix and integrate with the existing in order to highlight the volumes and the natural light. The private space (bedrooms and bathrooms) was designed around a thickness that acts as a patella, combining storage and access camouflaged by the moldings and mirrors which allows each of the rooms to gain in amplitude.