1 ECU / Euro Europa; 15 Countries

The ECU (European Currency Unit) was never legal tender in France or anywhere else — it was a basket currency used for accounting within the European Monetary System, existing only as a unit of account between central banks. France nonetheless authorized a series of commemorative issues denominated in ECU through the 1990s, riding a wave of pro-European sentiment ahead of the Maastricht Treaty's implementation. This 1996 piece, invoking fifteen member states, was struck just one year before the EU expanded to include Austria, Finland, and Sweden — meaning the count of fifteen was already obsolete within months of minting.