Gramps Is in the Resistance (1983)

It is 1943 in Paris. Like so many others, the Bourbelle family's home has been taken over by the Germans and they now live in their cellar. Little do they know that the son, Guy-Hubert Bourdelle, is far from being the cowardly hairdresser he pretends. He is in truth the Germans’ most feared opponent: le super-résistant!