@hollybrigstocke

I think my favourite French-ism imported into English is the phrase "cul de sac", which had friends of mine from France who were visiting England, in fits of laughter. In English, "cul de sac" is a rather twee, middle class euphemism for a dead end; in France it is a slangy and distinctly vulgar way of saying the same thing. The correct French term is "voie sans issue" whereas "cul de sac" literally translated into English means "the arsehole of a bag" and it's not 'twee' at all!