When the Nazis invaded France in 1940 he went into hiding; after many hardships, and the heroic assistance of Frenchmen, including Edmond Michelet and the American journalist Varian Fry, he was able to escape to Portugal with his wife, their son Franz, and their daughter-in-law.
Ketika Nazi menginvasi Prancis pada tahun 1940, ia menyembunyikan diri; setelah melewati banyak kesulitan, dan berkat bantuan heroik dari orang-orang Prancis, termasuk Edmond Michelet dan jurnalis Amerika Serikat Varian Fry, ia dapat melarikan diri ke Portugal bersama istrinya, putra mereka Franz, dan menantu mereka.