Recently transnational approaches have largely enriched the historical studies of the human and social sciences of the 20th century. Nevertheless, the research on that topic has been focused on the European and Transatlantic zone. In consequence, little attention has been paid to the circulations between “East” and “West”, especially during Soviet period. We could have thought, indeed, that the political instrumentalization of human and social sciences in the Soviet Union and the waves of repression against the intellectual milieus have isolated Soviet scientists from the rest of the scientific international community. However, as a matter of fact, Soviet politics did not interrupt scientific transnational phenomena. And many aspects of the history of the French human and social sciences remain incomprehensible without taking into account the circulations with East. It will be the subject of my talk. I will base my demonstration on the exemplar case of Marxism, which has been long considered as illegitimate in the French social sciences, because of the oppositions and criticisms of Emile Durkheim and his followers. That is only in the 1930’s that Marx and Engels ideas were really introduced in the French social sciences and gave rise to an original program of research in history of work and techniques. Its main defenders are young philosoviet intellectuals (Georges Friedmann, André Varagnac, André-Georges Haudricourt, Charles Parain et alii), playing mediation role between France and the Soviet Union. So, I will examine how their appropriations of the Marxist Soviet ideas were locally conditioned and allowed the academic legitimization of Marxism in the French Social science.