4 Francs, 60 Centimes, 1 Ounce French siege coinage

Zara — modern Zadar, on the Dalmatian coast — was besieged by British and Montenegrin forces in 1813 as Napoleon's Adriatic holdings collapsed. The city's French garrison, cut off from supply lines and running short of coin, melted down silver plate and church silver to strike emergency currency. The denomination itself, 4 francs and 60 centimes, was calculated to equal the value of one ounce of silver at the official French rate — a strictly utilitarian accounting decision that produced one of the most unusual denominations in European numismatics.

Only a handful of these are known to survive. The siege ended in November 1813 with French capitulation.