On January 17, the same day five American hostages were released from custody in Iran, a jetliner dispatched from the U.S. delivered $400 million in cash to Tehran’s Mehrabad Airport. Heightening the air of skulduggery, Iranian guards unloaded pallets loaded not with U.S. dollars but Swiss francs, euros and other foreign currencies.
http://fortune.com/2016/08/05/money-america-iran/
There were no euros in that year.