50 Francs Hercule Piefort

The Piéfort format — double or triple the normal planchet thickness — has been used by the Monnaie de Paris since the medieval period, originally as presentation pieces for official approval of new designs before full production began. By the 1970s, piéforts had evolved into a deliberate collector product, though they retained their archaic production logic: each required individual striking under substantially higher pressure to bring up full detail on the thickened flan.

The Hercule type itself dates to 1965, reviving a composition first used under the Third Republic. The 1974 piéfort reissue coincided with France's monetary restructuring following the collapse of Bretton Woods.