The collaboration between French and Russian mathematicians began during the first decade of activity of the Saint Petersburg Academy of science. It strengthened during the 19th century (let us recall the early carriers of Mihail V. Ostrogradskij and V. Â. Bunâkovskij, Pafnutij L. ?ebyšev’s contacts with Charles Hermite and other French mathematicians, Henri Poincaré’s correspondence with Aleksandr M. Lâpunov) and became an important factor in the blossoming of 20th century mathematical thought. The groundwork for this growth was laid by the Moscow school of the theory of functions, founded by Dmitrij F. Egorov and Nikolaj N. Luzin during the 1910s. Originating from the Russian branch of the French school of the theory of functions of a real variable (Émile Borel, René Baire, Henri Lebesgue), this school formulated its own original topics (Luzin, Dmitrij E. Men’šov, M. Â. Suslin, Aleksandr Â. Hinšin, Pavel S. Aleksandrov) and flourished (Andrej N. Kolmogorov, Lev S. Pontrâgin and others) setting the foundations of the Soviet mathematical school (with the Saint Petersburg/Leningrad school). The strengthening of Franco-Russian collaboration, in this context, followed the path of the theory of functions of a real variable and the directions of research associated with it (such as the theory of probability at the time). But it also led into new areas, such as different branches of mathematical analysis, differential geometry and so forth (Élie Cartan, Jacques Hadamard, Sergej N. Bernštejn, Paul Lévy, in addition to the scientists already mentioned). The events that preceded the Second World War brought this line of development to an end. Right after the war international collaboration started again, but Soviet mathematicians could take part only a decade later, after Stalin’s death, when the Cold War ceased, as is evidenced by the series of conferences given by Kolmogorov at the Henri Poincaré Institute in 1958.