False cognate: a French word that looks like an English word but has a different meaning.
Here's a stellar example from tonight's (actually Monday morning's) Le Monde article on the American election:
J-2: des meetings devant des foules toujours plus grandes"
Translation: "T-minus 2 days: rallies before still larger fools... er, crowds"
Somewhere, Le Monde's Washington bureau chief is winking at us.