International audienceThe « transitional lithic assemblages » and the Neanderthal speciation in Europe between 40–30 ka. In Europe, 14C dating provides various histories about the relationship between Neanderthals and the oldest Modern Humans who inhabited Europe. ‘Transitional cultures' have been identified these latest years in lithic assemblages according to the technical behaviour (Chatelperronian, Uluzzian, Bohunician, Szeletian...). According to the geographical areas, they could be the result of a local change of the Neanderthal groups or the proof of external influences. Some technical characters are linked to the Middle Palaeolithic behaviour (flake knapping, side-scrapers, denticulates, notches), while others are considered as Mod...