The french and japanese look very much alike from the outside, the differences I use, is that the french holster had loops for extra rounds, while the japanese had a pouch for two boxes of ammo. I think yours is a french one, as a japanese would also has a firing pin holder to the right of the cartridge pouch (when looking at it). OR, it is a Japanese type 26 - a revolver holster, see this
http://members.shaw.ca/tju/t26accessories.htm
Ed