His initial aim to reform Vietnam did not receive French colonial support. During World War II he collaborated with the Japanese and in 1945 he was forced to abdicate by the Vietminh. In 1949 he renounced his title and returned to Saigon as head of the state of Vietnam within the French Union. In 1955, after the partition of Vietnam at the Geneva Conference, he was once again deposed when power in the new republic of South Vietnam passed to Ngo Dinh Diem. He then went into exile, living mainly in France.