Definitely 1924 or earlier, otherwise you would not have 12 over a C in a diamond. It would be 12-65 inside a sort of capital C if it were later than 1924.
L'abeille means "bee" in French; reve is dream. So somebody had 5 dreams about bees???
I've seen guns marked L'abeille before but don't know anything about the maker. Not at all unusual to find Belgian guns sold by French shops, even though France had its own very active gun industry. I've currently got a Belgian 16 that has a Paris address (C. Mode) on the barrels.
