Found a tad more.
The full name is Maurice Cantarini, and he had at the same time a shop at:
37 rue de l'universite in Reims (Champagne).

This is really weird as my Dad went to high school literally around the corner.

The MC stamp was definitely applied by a barbarian (twice).
This does not reflect too well on the shop. However, the gun looks great. The maker also seems to have mis-stamped the SN once as the 4 of 1904 was over-stamped with a 0.
Best regards,
WC-