The Lavrillier 5 francs design had already been issued in aluminum by 1945, but the Paris Mint produced copper-nickel trial strikes — épreuves — in 1946 to evaluate alternative compositions as France sorted out its postwar industrial supply chains. Aluminum had been adopted partly out of wartime necessity, and these cupro-nickel pieces document the Mint's brief reconsideration of a denser, more durable alloy. The aluminum version ultimately prevailed in circulation. GEM 145.3 distinguishes this épreuve from the regular aluminum issue precisely because the composition never advanced beyond trial production.
The Lavrillier 5 francs design had already been issued in aluminum by 1945, but the Paris Mint produced copper-nickel trial strikes — épreuves — in 1946 to evaluate alternative compositions as France sorted out its postwar industrial supply chains. Aluminum had been adopted partly out of wartime necessity, and these cupro-nickel pieces document the Mint's brief reconsideration of a denser, more durable alloy. The aluminum version ultimately prevailed in circulation. GEM 145.3 distinguishes this épreuve from the regular aluminum issue precisely because the composition never advanced beyond trial production.