The fun thing about this hobby is your never know what your going to find. I took my daughters out with me today to hit a house I just got permission for. Found tons of clad pennies, dimes and quarters, one wheat penny and this 1939 French Franc. Love this hobby.
1970 COMPASS-
WHITES SILVER EAGLE-
WHITES DFX, 4X6DD COIL, 6X8DD COIL, 950 COIL, 10X12SEF COIL-
GARRETT PRO POINTER AT, GARRETT AT PRO , MINELAB EXPLORER SE with 8.5x12.5 Cors coil
Cool Franc, I dug an 1812 5 Francs here in Ohio. I agree the coins most probably came back with a soldier from WW II. Most of the foreign WW II coins I dig are large English Cents.
I was thinking the same thing as well. Odd finding it where I did. The house was built in the 30s or 40s, so great chance of being brought home from Europe like you said.