Correlation of geophysical and geological data with the western margin of the Bohemian massif, re-interpretation of the ECORS-DEKORP deep seismic sections, transformations and 3 D modelling of gravimetric and magnetic maps allow to define sequentional Saxothuringian and Rhenohercynian Paleozoic subduction systems in NE France and SW Germany where only 10% of the Early Paleozoic basement is outcropping. Two 35 km spaced and NE-SW trending gravity highs associated with SE dipping reflectors are interpreted as the western continuation of the Teplá Devonian paleo-subduction zone of the Saxothuringian ocean and Early Carboniferous underthrusting of the Saxothuringian passive margin, thereby defining the Saxothuringian subduction system in west Europe. South-eastwards dipping reflectors beneath the Moho are interpreted as witnesses of the Early Carboniferous subduction of the Rhenohercynian ocean. The suture is marked by the gravity high in the phyllite zone of the southern Rhenish Massif. Gravity lows in the SE of gravity highs and weak ondulating reflectors are interpreted in terms of crystalline bulges in the hangingwalls of sutures. The numerous highly magnetic anomalies correspond to magmatic bodies emplaced in the time-range 335–330 Ma, along NW dipping and sinistral normal faults. Located in the hangingwall of the Rhenohercynian subduction zone, this wide magmatic arc trends obliquely with respect to the Saxothuringian subduction system, which is almost obliterated by the wide front of magmatic bodies.