To assess the influence of climatic changes on organic lacustrine sedimentation, two cores recovered from the centre of the Lac du Bouchet were studied by petrographical (palynofacies and geochemical methods. Only core LDB H was used for estimation of the organic fluxes. The variation of these fluxes with climo-stratigraphic periods showed: low organic fluxes during the Lateglacial, an increase at the beginning of the Holocene, a minimum at the end of the Atlantic period resulting from the climatic cooling, and a maximum at the end of the Sub-Boreal related to the installation of the present climatic conditions.