The idea of a sanitary belt against the Russian influence comes back periodically in the forefront of security discussions in Central and Eastern Europe. The line joining the Baltic Sea from the Black Sea to the Dniester, or the Ponto-Baltic isthmus as named by Simion Mehedinti in 1916, was and is a major security landmark for Russia and Europe. Thus, the Dniester has become the strategic line that separates the two major geographical and geopolitical spaces, always being applied a “geopolitics of the sanitary belt” in the region. In the second decade of the twentieth century, the fear that the socialist revolution extending throughout the European continent determined the great powers to condemn from the beginning the new Soviet political regime and to seek solutions to limit its influence in Europe. The idea of an anti-Soviet front from the Baltic to the Black Sea, proposed by the states in the region directly threatened by Soviet danger as Romania and Poland, was supported only by France, the other great powers being determined to make peace with Soviet Russia. Starting from the assumption “new arguments, old geopolitics”, we propose in this study, which is primarily historical, the analysis of this key moment in the foreign policy of inter-war Romania, in which such a project for the realization of a sanitary belt against the Soviet influence was promoted, and in which Romania and France have played a decisive role. We will follow the evolution of the idea of sanitary belt analyzing foreign policy articles from the Romanian press from 1920-1921, but also the position of the great powers against this idea, and especially France’s role in reconfiguring regional geopolitics.