Is there an organized resistance building up in the currently occupied countries?

Hi Indy and crew

Since the occupation of Poland, France and the low countries are now several months old. My question for OOTF is: Is there any record of organized resistance in those countries this early in the war or are there old networks in Belgium from The Great War that reactivated in this war? If they were already active where did those networks build up and how did they resisted the Nazi’s?