2 Francs - Honoré V

Honoré V ruled Monaco under conditions of near-total French financial dominance, and his silver coinage was struck in tiny quantities — Monaco had no mint of its own and relied on contracted production, leaving these issues chronically undersupplied relative to the principality's needs. The series is notoriously difficult to complete by date and condition precisely because so few pieces entered general commerce.

The Gadoury reference places this squarely among the rarest 19th-century Franco-sphere issues.