The excavation of Riencourt-les-Bapaume marked a decisive methodological turning point for Prehistory in the North of France. For nearly thirty years now, systematic archaeological testing has been carried out by specialized teams for the detection of Paleolithic sites as a result of development and construction projects. The regular construction of large linear projects (A16, A29...) has allowed the collection of a large volume of data. A chrono-stratigraphic framework of Paleolithic human occupation has thus been established and has now reached a level of resolution unparalleled at the European level. This detail ¬makes it possible to highlight the variability of lithic industries over the long term according to the chrono-climatic phases, and ultimately to identify distinct and coherent cultural groups. In the case of linear projects, discoveries are most often followed by systematic excavations. ¬ These large-scale excavations have made it possible to understand the internal functioning of the deposits, notably through the dynamic study of the soil stripping, but also beyond the site itself to the landscape scale thanks to the immense dimensions of the areas studied. Based on reoccurring behavioural evidence observed on several sub-contemporary sites, a hypothetical reconstruction of territories can also be attempted. Along with these large linear projects which are exceptional (in time and the resources allocated) the usual operations are often small and are sometimes limited to in-depth testing. Discoveries are too rarely followed by excavation but they are fully in line with current research programs.