To be fair, MacDo is quite decent in France. But honestly, the invasion of American chains needs to stop.

Sure, it's totally fine to go to a café and pay small amounts in coins. But please don't pay for a 30€ restaurant bill in coins. Legally acceptable as mentioned, but the server would be pissed in the same way as if you tried the same tactic in the US or anywhere else in the world.

Or failing that, if you need to go to a hypermarket/supermarket, many of them have a coin-counting machine that takes all your coins and issues a store voucher for that amount. I think like Coinstar in the US.