50 Francs - Rainier III Piedfort Essai

Piédfort essais from the Monnaie de Paris are production-authorization pieces struck at double or greater thickness on specially prepared planchets — not patterns in the experimental sense, but official proofs of die quality submitted for administrative approval before a series enters circulation. Monaco's postwar coinage required French mint cooperation under the 1951 Franco-Monégasque monetary convention, and these essais document that process directly. The gold version of this type is among the rarest tier of the Monaco essai program; most piédforts from this period were struck in silver or copper, with gold reserved for a handful of presentation examples.