The "French" Resistance was a Stalin initiated and controlled front operation. French "resistance" did not appear during the entire first year of Germany occupation after June 22, 1940 - when the Hitler-Stalin pact was in effect. It was not until after the June 22, 1941 German invasion of the Soviet Union - on June 22, 1941 - that the 1st "resistance" attack occurred in France. That was the August 21, 1941 assassination of a German officer.
As for Raymond Aubrac's background before WWII, here's from the machine generated translation of Wikipedia French article on Aubrac (LINK):
"During these student years, Raymond attends Labour University, a study circle {of} Marxist Communist intellectuals."
The article continues with his post war career as a Communist collaborator, sympathizer and asset. It was one of various government positions under Communists as their closest and most trusted fellow traveler dancing to every tune they played.
In 1946 he even had Ho Chi Minh living with his family in Paris for several months (and makes Ho "godfather" of one of his daughters) before Ho returned to Vietnam to begin the First Indochina War (against France) in late 1946.