Part of the pre-existing building is demolished in order to free the bell tower, hidden since centuries, eliminating  the existing urban tensions. A new metal body is built, which dialogues with the part of the building that is maintained. A courtyard is left  to the NW, at the foot of the Gothic tower to allow the access to the future public space in the center of the urban block.

The new body, with a metal skin, lined with bookcases on the inside, gestures and dematerializes when it finds the tower, turning the common void into a shared space, and making that the real enclosure  of the box, its fourth façade, are the ashlars of the Gothic bell tower.

Between new and old, a 'slit' of light and air, allows to visually relate all the floors of the equipment and enhance the dialogue between interior and nearby urban space.