 Complete the following phrase:  Following a brief stay in Demark in 1934, Chakhotin took up residence in France where he obtained a succession of posts in the Collège de France, the Institut Prophylactique de Paris, the Hôpital Léopold Bellan, and the Institut de biologie physico-chimique. During most of his time in France his material situation was precarious. Politically he became involved with the radical wing of the SFIO, in particular with Marceau Pivert and Jean Zyromsky and the Jeunesse Socialiste where he established himself as an authority in anti-fascist propaganda. By 1936 he had became an assistant to Marceau Pivert, eventual Secretary of the Federation of the Seine of the SFIO and head of propaganda for the SFIO at the outset of the Popular Front government. The Three Arrows symbol became current in the propaganda of the SFIO and of Piverts group, the Gauche Révolutionaire. In 1939, his key work was published in Paris. Shortly after the release, it was removed from bookshops by the French police, and was formally banned, with copies being destroyed when the Germans occupied France in 1940. In June 1941, following the 