French-US monetary history after WWII:
Under the Bretton Woods agreement (1944-1971), the US dollar was the world’s reserve currency, and it was pegged to gold at $35 per ounce. Other countries pegged their currencies to the dollar.
around 1965, De Gaulle initiated a systematic, aggressive policy where they converted USD into physical gold every time French acquired USD from trade, then French Navy picked those gold bullions from NY. By 1971, the US gold reserves had decreased so much that they did not cover the dollars circulating globally and Nixon "closed the gold window,"