Many people did not agree with him when he supported the German occupation of France during the Second World War. He played in some concerts which were supported by the Nazis. He may just have played at these concerts because he liked German music, but it made him some enemies. His wife, Clothilde Breal, was of Jewish origin and her cousin, Lise Bloch, was married to Leon Blum, the first Jew to become President du Conseil or Prime Minister in France. Cortot and the Blums were good friends, although he was banned for a year from performing in France.