Hello,
I don't call myself an expert but I can help.
I haven't got an example of the mark with 'France' added to it, but this is the closest I could get, I guess. It's the only round mark and there is a whole range of signatures used from 1949/1950 with either Paris, France or both added to the name. From 1955 up to the end they have gone back to just the name without circle/oval etc ... acid marked, sand blasted or diamond point signature.
This round mark was used around 1949/1950 for the new company, SARL Cristallerie Schneider, founded by Charles jr and his brother Robert-Henri.