During the 20th century, faced with the transformations of diplomacy, France had to undertake a major re-equipping of its chanceries worldwide. While previously the practice of "diplomatic repurposing" (absorbing pre-existing buildings) had been the norm, after the First World War France sought to expand the number of its new facilities – the Ministry of Foreign Affairs then commissioning carefully selected architects. Although these architects were often Prix de Rome winners, the Ministry of Foreign Affairs demonstrated a rather open approach in its choices – employing architects with academic training, certainly, but who had reinvented their practice through the lens of modernity. Thus, France's external image gradually evolved from a modernized tradition between the two world wars to the assertion of a modern signature during the post-war period and the Trente Glorieuses (Thirty Glorious Years). After a general overview, special chapters discuss the work of Roger-Henri Expert in Belgrade, Eugène Beaudouin in Ottawa, Georges-Henri Pingusson in Saarbrücken, Le Corbusier and Guillermo Jullian de la Fuente in Brasilia, Bernard Zehrfuss in Warsaw, André Remondet in Washington, and finally Christian de Portzamparc in Berlin. The unrealized projects of Claude Parent and Guillaume Gillet, among others, are also mentioned. This evolution of French diplomatic architecture during the 20th century deserves special attention, through the most significant embassies designed by leading architects. These buildings thus allow us to trace a different history of modernity in France, from the perspective of its institutionalization and international dissemination.