1 Centime pattern, Gengembre process

In 1796, the Directory-era Monnaie de Paris was experimenting with alternative striking methods to address chronic shortages of viable coinage metal. The Gengembre process — named for the chemist who developed it — involved treating tin to improve its hardness and surface stability, making it a plausible substitute for copper in small denominations. These centimes never reached circulation; the process was ultimately abandoned as insufficient for production-scale durability.

The variant designation in Mazard reflects genuine die differences among surviving trial pieces, suggesting multiple striking sessions rather than a single proof run.