Evidences of Lower and Middle Palaeolithic human settlements in sub-Saharan West Africa are relatively uncommon, poorly or not even dated, and come from surface sites or secondary stratigraphic context. The discovery, within the international research programme "Palaeoenvironment and human settlement in West Africa", of an impressive Pleistocene sedimentary sequence with numerous archaeological levels in the sector of Ounjougou (Dogon Country, Mali), is thus of great importance, insofar as it allows us to set up a first chrono-cultural reference framework for the West African Palaeolithic. Although the exact chronological position of a Lower Palaeolithic human settlement has yet to be specified, the recurrent Middle Palaeolithic occupation, between the end of marine isotope stage 5 and the beginning of stage 2, reveals an astonishing cultural diversity. This could indicate an important repopulating activity, following climatic and environmental changes during the Upper Pleistocene. Particularly, the appearance of the Levallois reduction technique in Sahelian West Africa, possibly prior to the emergence of the Saharan Aterian, leads us to reconsider the question of the origin of this reduction concept introduction in sub-Saharan West Africa. More generally, the Palaeolithic sequence in the sector of Ounjougou shows the intrusion of more southern and/or eastern cultural influences.