In a post-structural perspective that is part of historical anthropology, this thesis describes the phenomenon of recent ethnicisation of groups that identify themselves as being misled in eastern Canada. The aim is to understand this event by addressing it as a cultural process and qualifying it as culturalism. The analysis is mainly based on interviews conducted in several regions of Canada with individuals of Canadian and French origin who assert their indigenous heritage. The political organisation of Eastern Métis in recent decades has led to a confrontation of prospects with the dominant socio-cultural order. The Canadian authorities express serious reservations about this increasingly pressing request for recognition. Rather than sticking to this politicolegal dimension of the phenomenon, the thesis shows that there are cultural resistance, logic, world visions and collective memories that are difficult to reconcile on both sides. This argument focuses in particular on the concerns of Métis for cultural continuity, in particular with regard to the supply of game and fish for food purposes. They are aware that aspects considered central to their cultural heritage are now under threat, especially in the context of the development of capitalism and its repercussions on the socio-political scene. They call on their memory and express their collective shared awareness of change, of an alteration of their specificities, which represents the cultural reason for their ethnic affirmation. The thesis responds in an unprecedented way to this ethnicisation phenomenon through its comparative and multi-location approach, but also through the use of field data that are still poorly exploited in spurious studies in eastern Canada. The post-structural perspective is likely to provide a better understanding of the challenges and challenges that have arisen since the end of the 19th century for East Metis. I intend to check whether the culturalism of the Métis represents a moment for culturally specific collective action in the face of unique events.