10 Centimes Epreuve double revers en aluminium de Lindauer

In 1939, the Paris Mint produced a series of aluminum trial pieces exploring emergency coinage compositions as war made traditional base metals strategically sensitive. This double-reverse épreuve — struck with two reverse dies and no obverse — is a technical trial of the kind routinely produced internally at the Monnaie de Paris to test die alignment, metal flow, and alloy behavior before committing to production. Lindauer's design had been in circulation since 1914; the question here was never the design but whether aluminum could be made to strike cleanly at this module.

Full aluminum coinage for the 10 centimes denomination never materialized before the Occupation changed everything.