Some Gtane TdF's were built without an integral derailer hanger. It seems strange to see a high end 531 frame with a claw, but there are a lot of things about French bikes that seem strange.

I didn't know that Mafac Competitions existed as early as 1970. Peugeot didn't make the switch from Racers until 1974. My Gitane TdF has original Competitons, but I've only been able to narrow its build date to somewhere between 1971 and 1973.

I see you have the optional Campy hubs. You're lucky!