The trick is to teach French learners that this word means something in French and at the same time to teach English learners that it means something in English

The trick is to teach French learners that this word means something in French and at the same time to teach English learners that it means something in English. So you travel to France and practice your newly-learned French. You run across a French person who has been learning English. You use the word thinking that it’s French, and the person you speak to has already heard it as an English word and thinks that you don’t know the word in French but they know what you mean thinking it’s an English word.