The western termination of the "Risoux nappe" of the High-Chain of the Jura mountain range (Ain, Haute-Savoie. France), is a combination of a major anticlockwise strike-slip fault (Vuache-Forens-Les Bouchoux fault) and of a zone of strong deformation of the sedimentary cover to the West of the fault ("faisceau de Champfromier"). Multiphase deformation with changing directions of stress and strain is at the origin of these lateral ramp structures: S-N folding starts in the Early Miocene; the whole sedimentary cover of the area is dislocated to the West in Late Miocene and Pliocene and S-N compression or E-W distension is indicated by the actual seismicity. Basement faults are argumented to exist along the Vuache fault and to the North and West of the Bellegarde plateau with a prolongation into the eastern flank of the Grand Colombier anticline.