The Molitor building by Le Corbusier is located between two distinct areas in Paris, on one side are the athletic parks that covered the ancient fortifications to a depth of 200 meters, and on the other are the gardens that occupy the foreground of Boulogne. The horizon is dominated by the hills of St. Cloud and Suresnes.
At the Fourth International Congress of Modern Architecture in Athens, Le Corbusier claimed that the elements of planning were: the sky, trees, steel and cement, and in that order and hierarchy. He claimed that the inhabitants of a city who lived with these elements would find themselves holding what he called "essential joys". This building serves as a control or prototype. Building regulations in Paris at the time meant there were restrictions for the alignment of buildings to the street. The position of the site was deeply imbedded within the existent urban fabric, hence a challenge arose to design a solution which communicated to the surroundings landscape.
Utilising the benefits of the the front facade, the building was formed by two pieces of glass placed in front of concrete floors. Each apartment has therefore an entire wall of glass, from floor to ceiling. This meant that design solutions were instigated to close off the light within each apartment. The building is occupied and the tenants declared that a new life began for them, thanks to the device of the glass panel, integrating the 4 elements of Corbusier's 'essential joys'.
The ground floor houses the lobby, domestic services and indirect access to the underground garage. The apartments are spread over six floors in groups of two or three, according to the demands of the buyers. Two patios, one small and one larger, connect the apartments to the 'sky and trees'.
At the seventh floor apartment is the house and studio of Le Corbusier. This is accessed by the lift of the building. The top floor is covered with barrel vaults, maximizing regulatory dimensions. The light of the setting involves the rooms facing the street de la Tourelle, in a continuous succession where the bathroom merges with the bedroom. A large revolving doors leading to the study, home office and a corner of a small room. The masonry of sharecropping, uncoated, provides a background to the room irregular. The terrace is accessed by a spiral staircase.
The initial design included a steel skeleton, but was replaced by a concrete structure, for a lower cost. An axial row of piles on the site allowed free placement of partitions. On the top floor, there are barrel vaults, these were made with a reinforced concrete building system, conceived between two flat plates whose height extended in spaces adjacent to the facades, which is also covered with concrete vaults. In the workshop, the vault is a plain white sheet that overlaps the planned cut in the upper plate of the terrace garden. The vaults on the perimeter do not require supports and dintelar walls, which visually opens the luminous space with the skyline of Paris. Second, a gap is left between the ceiling and the dividing wall, suggesting the effect of an expansion of vertical space increases with overhead light rays by incorporating high windows.