Dug up this thread as I've just acquired a Gitane and am trying to make sense of the numbers. Not succeeding, so far.

This is what I've found on the NDS dropout. Nothing I'd call evenly stamped and spaced:



This is what the bike looks like:



It has a French Reynolds decal indicating butted 531 frame tubes, forks and stays. (Date) codes on both Mavic rims and on the Huret Challenger rear derailleur say "0275" (if my eyes don't deceive me). Frame size is 52cm (C-T). The closest match I've found in the catalogues is the 1975 Super Evry: