Even though Monaco has only 0.76 square miles of area, nobody told them they couldn't be a country. So they are. Uniformed, they mint their own coins and Nico has one nice-looking example.
(Sorry, Nico -- Since your coin has a hole in it, it is worth zero. Collectors will not buy holed coins.)
The coins of 1, 2, and 5 franc denominations are made of aluminum and have the portrait of Louis II, who reigned from 1922 to 1949. The 1 franc and 2 francs do not show dates, but the 5 francs does. Coins with this pattern were minted between 1943 and 1945. There are other patterns for other years, but this page applies only to the pictured coin. Also, there are gold coins (they are valuable) with the same and similar patterns. This page applies to the non-gold versions.
Here are some typical values for 1 franc:
worn: less than $1 US dollar approximate catalog value
average circulated: $1
well preserved: $5
fully uncirculated: $10
For 2 franc coins, multiply these values by 2. For 5 franc coins multiply by 4.