The Paris Basin is an intracratonic basin made of Meso-Cenozoic sediments unconformably overlying a Variscan substratum (Figure 1). Deciphering the geology beneath its sedimentary cover is important for at least two reasons: (1) the area is a "data gap" in the middle of an important segment of the Variscan belt in Western Europe, and (2) the role of the structural inheritance on the Meso-Cenozoic sedimentation is not fully understood yet. The basin basement is roughly made of two different geological units, namely (1) the Variscan substratum sensu stricto, made of heterogeneous deformed sedimentary, magmatic and meta-sedimentary rocks, with minor meta-magmatic rocks, and (2) the late Variscan (late orogenic) Permo-Carboniferous basins, made of thick siliciclastic sedimentary deposits. These two geological basement units have their own geological characteristics and geophysical properties, which are fairly different from each other. For that reason, they must be investigated using dedicated methods. Seismic methods were implemented for studying the Permo-Carboniferous basins. Based on the reprocessing and interpretation of several thousands of km of seismic lines, we propose a new location and thickness map of the Permo-Carboniferous basins. On the other side, potential field methods were used for mapping buried polygenic basement rocks. Based on the combination of aeromagnetic and gravity data, supported by petrophysical signatures and field/borehole geological information, we propose a new map of the architecture of the Variscan substratum.