They didn't repatriate the gold in the sense of physically moving it from the US to France. Instead, they sold the gold that was held in the US and used the money raised to buy gold from other sources, which is held in France.
Different gold, and two financial transactions, accounts for the financial gain.
Yes but the article implies that they somehow made 15B in profit by selling the gold in US and buying an equivalent amount which can’t be the case.