Historians Pierre Renouvin and Jean-Baptiste Duroselle have extended the practice of diplomatic history to transform it into the history of international relations, a history of the relationships between peoples, not only state. The former, by inventing the notion of « deep forces », has attempted to measure the weight of demographic and economic forces, the weight of mentalities and great collective feelings on the evolutions and quakes of international relations. The latter has studied decision processes and has endeavoured to determine how decisions-makers have been influenced by these deep forces and, equally, how they could outweigh them, bend them, or transform them. Forty years after, French historiography of international relations is still living largely on the two « masters » heritage. They have renewed perspectives by borrowing largely from economic, political, cultural and representations history ; they also have played an important part in turning traditional military history into a political-strategic defence and security history. The great interpretations established by politics specialists arouse the historians’ interest, as well as their perplexity. As the historians’ will is to communicate the complexity of past reality, it is difficult to force it into an exclusively « realist » or « idealist » or « functionalist » or « constructivist », etc., reading grid. Let us say that the historians’ natural realism is tempered by a constructivist approach and by the necessity to take into account the importance of ideas, ideals, values and great collective feelings which overturn traditional power relationships. Nevertheless, they must not be satisfied with combining the different schools’ works together. Their originality lies in their reflection on time : they must think historically the dialectics between the « international system » and international, or trans-national « dynamics », woven into diverse temporalities, that transform ceaselessly the system order. –Summary AFRI-2003