The new spaces have been clearly differentiated from the existing structure by using a specific architectural vocabulary. The three main spaces (reception, passageways and reading rooms) have been treated with distinct plasticity that creates a dialogue with the monumental architecture.

The operation relied on the one hand on removing parasitic elements that interfered with a reading of the original quality of the volumes, and on the other, on building a vertical movement system and creating new functional floors. The objective in removing the parasitic features was to make the volumes under the dome accessible and visible to the public, including the non-reading public. The library’s identity is embodied in this exceptional volume.

The monumental staircase lies at the actual and symbolic heart of the rehabilitation. Its 27 meters give access to each of the library’s floors. Composed of 120 12/12 mm stays, the staircase rises in a spiral that unifies the building and simplifies how it is read. Above all, it helps reveal the building’s original dome, thus conferring on it its former glory. More than just the primary function of facilitating human movement, its 78 steps become landings where people can meet. So as to provide ambient quality that encourages reading, working and conviviality in the cleared space, four platforms have been created in the perimeter around the great atrium.

Replacing the former platforms, this arrangement frees up the comfortable heights under the ceiling for spaces accessible to readers. Vertical traffic hubs have been placed in the corners of the new platforms. These corners, corresponding to the four former courtyards, have thus become the nerve centers for the efficient functioning of the new library. They thus liberate the major volumes intended for the public from technical contingencies and safety. This arrangement enables comfortable working conditions for the staff and provides visual comfort for the big public platforms.