Hi All
After looking at the larger scan of this perfin, I have reason to believe that it is possibly either an "OL" perfin, or from the face side an "LO" perfin.
If you all look closely at the upper corner where the perfs are, you will see that they protrude far into the stamp and that may be part of the design on the face side. There is enough space used up to conclude that the last initial could very well be an "O" and NOT a "C"
Having said this, if it is an "OL" or "LO" perfin, than I can offer no information about the user as it is unknown at present - at least to me

Had it been a "CL" perfin as originally thought, then yes, it would have been Credit Lyonaiss.
Sorry for any confusion this may have caused.
Cheers
Bujutsu