A few French 1st release posters are so rare most sellers don't even know they exist until one eventually pops up.
Take my double panel French Gone with the Wind poster. It is quite unique and probably the only copy out there. The re-release, with faded colors, has been sold as an original for ever, because no one had ever seen the first printing. No wrongdoing there. If you put both of them side by side, the difference is flagrant, but if you've never seen the first one, the re-release looks great. It happens a lot.
I'll post it later on.
T