Okay kiddo, so sometimes people from one country might use a word or phrase that comes from another language. When French words or phrases are used in English, it's called a gallicism!
For example, "bon appetit" means "enjoy your meal!" in French, and some English speakers might say it before eating. Another gallicism is "rendezvous," which means a planned meeting, and is originally from French.
Gallicisms can make our language sound fancy or sophisticated, but sometimes they can be confusing too. So it's important to make sure the person you're talking to understands what you mean!