The excavation of the open-air site of "Hauts de Buffon" led to the study of a Magdalenian occupation made up of two concentrations several metres apart. In the absence of faunal and organic remains, the study is only based on the abundant lithic industry discovered at the site. This latter is similar in each locus and post-depositional phenomena did not modify the general organization of the remains preserved in the only archaeological level identified. This good general conservation brought to light the complexity of the activities carried out on site, as well as the different behaviours linked to the acquisition of raw materials and techno-economic activities. The raw materials brought to the site show that procurement was mainly centred on distant materials from the south of the Paris Basin, but also from Limagne in Auvergne. This behaviour indicates the anticipation of raw material needs, but also the high mobility of the site ocupants, as shown by the exportation of finished (non-retouched and retouched) products from the site. The different characteristics of the raw materials brought to the site are used for different debitage aims. The lithic industry combines good quality distant raw materials with the production of well-made laminar blanks, knapped with an organic hammer, following an elaborate schema. Local and very accessible raw materials are reserved for simplified laminar production obtained with a soft mineral hammer. The bladelets result mostly from separate production on small modules. These technological aims are also visible for blank management, with blades used as blanks for domestic tools and bladelets for armatures. The panoply of