The Voirons Flysch (Haute-Savoie, France) is the subject of the present research. In this study we propose (i) a refined age model based on planktonic foraminiferal biostratigraphy, (ii) the extension of the reworking process and (iii) a structural study suggesting an updated tectonic model for this flysch. Based on the determination of isolated specimens, ages for each member of the Voirons Flysch have been suggested. It could be deposited between the late-Middle Eocene and Late Eocene or Early Oligocene. The extension of the reworking suggests one (or more) rock (s) source (s) of Early Cretaceous to early Middle Eocene age. The structural analysis shows that the Voirons Flysch forms an open conical fold (suggesting fold amplitude attenuation) with dip variations about 20º. The relative homogeneity in stratification orientations observed suggests that no major tectonic disturbance can be recognized between the members of this flysch.