100 francs - Rainier III piéfort or

Piéforts — struck at double the standard planchet thickness — have been a deliberate collector production in French and Francophone minting traditions since at least the 17th century, and the Monnaie de Paris has long handled Monaco's coinage under successive bilateral agreements with the Grimaldi administration. This gold piéfort for 1982 would have been produced in extremely limited numbers, almost certainly in the low hundreds, as was standard for Monnaie de Paris piéfort issues of this period.

The .920 fineness reflects the older French coin gold standard rather than the .999 fine bullion conventions gaining ground in the early 1980s.