Since the work of memory cannot exist without inter-subjective exchanges, this paper introduces in the study of memory the concept of « social acting » created by Weber. Attempting to point out the plurality of the practices that feed the various forms of socio-memorial movements present today in France and elsewhere. Which are the processes taking on a very particular aspect in post-genocidal as in post-migratory situations such as after the Shoah (Khurbn in Yiddish) ? In the case of the Ashkenase, these processes are also post-ethnocide and consist in a qualitative re-inscription within genealogical mapping and simultaneously in the long development of a history in which the genocide constitutes a memorial screen as well as actions of re-inscribing and re-connecting with cultural markers associated to periods antedating the genocide and ethnocide.