It seems, however, that Rau also had influential friends. He was released from prison and expelled from Spain. He moved to France in May 1938. There, he was in charge of the emergency committee of the German and Austrian Spain fighters and member of the KPD country leadership in Paris until 1939. At the beginning of 1939 Rau crossed the border to Spain again and subsequently led, together with Ludwig Renn, the remainders of the XI Brigade. Together with other remaining international units – now combined in the "Agrupación Internacional" – they fought on Spain's northern border after the fall of Barcelona, protecting the stream of refugees escaping to France. Thus the Agrupación enabled the escape of perhaps some 470,000 civilians and soldiers.