These coins were made by the hundreds of millions, were worth next to nothing when they were issued, and I am sure most people discarded them or put them away after the liberation from Germany. Extremely high grade (mint state, flashy with no contact marks) brings some small premium, and there are a couple rare weight varieties as the Vichy government was instructed to reduce the weight to conserve aluminum, and sometimes the wrong planchets were used. Odds are, this is not a rare type, and to a collector is worth less than a dollar, if anything at all. A thoroughly mixed bag of older world coins will usually have several of these coins; I amassed nearly 20 just as lot bycatch.
This coin has a story and ties to your family - that is something money can't buy! Did your grandfather get this from circulation in WWII, or after the war was over?