I just found a 1939 French Indochina 10 cents while CRH. I'm not very familiar with this coin, but I tried do some research. What I found was there were 2 version of composition. Nickel and Copper Nickel. Mine doesn't stick to a magnet so I guess Copper Nickel am I right? Also, mine is no dots date. Was it a rare coin? Thanks alot guys!
Neither the nickel or copper-nickel varieties is magnetic, and other than the color (this looks like the copper-nickel one, to me) I'm not sure how you'd tell the difference. This one is https://en.numista.com/catalogue/pieces7155.html as far as I can tell, and unfortunately the mintage is combined between this and the one with dots beside the date. It does not appear to be rare.