Although the shoah unfolded in all its horror only during the early 1940s, long before that it was already clear that the situation in Germany was only going to get worse, especially for Jews. Towards the end of the 1930s the Olievensteins escaped to France. By 1942 the French puppet government was beginning to round up Jews in the southern half of France, where most had congregated to get away from occupied northern France (Approximately 50% of the Jews in Metropolitan France were by this time refugees from Germany or from territories recently over-run by German forces.) For those gathered up, deportation to death camps in Germany followed. The Olievensteins, however, having avoided extermination by escaping from Germany to France, now avoided extermination a second time when they refused to comply with the government requirement that Jews should identify themselves by always wearing a Yellow star where it could be seen. Following a childhood which taught him to conceal his Jewish provenance, after the nightmare ended Claude Olievenstein's family settled in Paris, city which he would quickly come to love: "Now we had our place in the world. We had the right to be ourselves, the 'Jewish problem' had ceased to exist". It was in Paris that Claude Olievenstein undertook his studies in Psychiatry. As a young man be briefly joined the Young Communists, but was in the end excluded. He became one of the leaders of the Union of French Jewish students: his Jewish identity was always very important to him.