Interesting point. Wouldn't an individual Frenchman see a USD as a token for metal until the shock? And until the shock, national currencies circulated at a fixed exchange with the USD - thereby his own currency was effectively gold backed?

At a national level, yes the Central Banks settled in gold, but that was after the micro transactions bubbled up to be settled from the commercial banks and then eventually cleared at the Central Bank level (Talking on the edges of my understanding here - just trying to see if the reality for an individual level was the currency was gold backed until 71).