10 francs Millénaire capétien piéfort or

The Capetian millennium commemorates Hugh Capet's election as King of the Franks in 987, the dynastic foundation that would eventually produce the Bourbon line. Piéforts — struck at double or greater thickness on standard-diameter flans — have been a Monnaie de Paris specialty since the medieval period, originally produced as presentation pieces for assay officials and tax collectors to verify correct coin weight and design.

At nearly 39 grams in .920 gold on a 26 mm flan, this piece is dramatically thicker than the circulation strike, making edge examination a reliable first check for authenticity.