Hi David

Please refer to the following Coinquest page ...

https://coinquest.com/cgi-bin/cq/coins.pl?coin=19239

https://fr.numista.com/catalogue/pieces251.html

Luxembourg 1 franc 1964. Here's one that sold for 99 US cents on eBay:

https://www.ebay.com/itm/203233131713?hash=item2f51a37cc1:g:AWMAAOSwY0lXRuOH