The architectural party begins with a simple geometrical consideration: the minimum footprint of the library is the one of the level combining the most important reading areas. By respecting the setback imposed in south end of the plot, this footprint approaches a square shape. Due to its unique character with a visible sculptured ceiling from the outside, it becomes a level of visual reference. Below, the Forum, high and bright, connects city and garden. It is inhabited by volumes of more intimate size which, on the scale of the pedestrian, break the linearity of facades. Above, the levels of consultation and offices decrease on surface and are hollowed out as we rise in floors.
These spaces define spaces in double height, diffusing the light from the facades inward; a central atrium connects visually three levels of consultation, and diffuses the light from the centre. The simple envelope of the building is modelled, by setback places or in projection, according to the uses and the orientations: caps in the South to limit the solar contributions summer, terraces of reading in the southwest angle. These sets of volumes modify the reading of the building, the square or the garden.