An office building composed of two buildings dating from the 1970s, frames an interior garden of approximately 5,500 m². Its restructuring is an opportunity to requalify all the exterior spaces into a coherent, qualitative and sustainable landscape. The project plans to introduce a strong vegetal presence in the form of a miniature forest uniting the two levels. This unified landscape is crisscrossed by paths that multiply situations. The technical constraints are decisive. The challenge is to achieve a common writing, despite the differences of the locations. Planting on slabs requires a technicality that we have developed in many projects. The garden on slab is made up of a constant layer of soil of about 80 cm, shaped by islands of vegetation thickened by a filling of expanded polystyrene blocks. It incorporates the planting of trees always  arranged in line with posts of the parking structure. The open ground part is densely planted (1 tree / 14 m²). All the paths are particularly well maintained. The embankments that surround them are the foregrounds where the ground covers of a rich and abundant undergrowth are implanted. They constitute gardens in a wider landscape whose simpler ground covers do not require such meticulous maintenance.