Zig-Zag was the codename of Eddie Chapman, a criminal imprisoned in Jersey for safe-breaking[?] in Glasgow. On the occupation of the Channel Islands, the Germans recruited him as an agent and despatched him to mainland Britain to commit acts of sabotage. He was turned and was used to feed misinformation to the Germans.
... Mitterrand joined it 1943.
There were other resistance groups like Liberte and Verite (that merged with Combat) and Gloria SMH (that was betrayed). Later Combat, ...