The northwestern Mediterranean has been an area favored for bioanthropological and biogeochemical investigations for almost 20 years now. Recent studies have demonstrated that, contrary to previous thought, the diets of Neolithic people were highly diversified and could be influenced by the organizational system and specific mobility of the people. Due to the presence of numerous single burial sites in southern France, most of the stable‐isotope data obtained on human remains come from the Early–Middle Neolithic periods. Currently, very little data are available on the late Neolithic and early Bronze Age. This study presents preliminary research on collective burial sites in this transitional context. A bioarchaeological analysis combined with a multi‐element (CNS) stable‐isotope analysis on human (n = 28) and animal (n = 12) bone collagen was performed for four sites in Southern France. This area provides an exceptional environment where wild and domestic terrestrial resources can be exploited, as well as river resources. Settlement documentation for the area is rare, and no relationship analysis can be performed between the burial sites and the little archaeozoological/archaeobotanical data available for the area. Although this investigation is preliminary, our results demonstrate the importance of domestic herbivores in the protein portion of the human diet, and we cautiously suggest a shift between caprine and bovine sources during the transition to the early Bronze Age. The sulfur data also indicate different environments exploited for some individuals and possibly different geographical origins, without the influence of biological (health status, sex, or age) and/or cultural (funerary treatment) parameters.