"You are a big person."
Translation:Tu es une grande personne.
There isn't a distinction in English, but that doesn't matter in French. The gender of the word 'personne' is always feminine, even if you know full well that the person in question is a male or even if you don't know anything. The French will read 'une grande personne' and see the same as us though - just because the word is feminine, they know that doesn't mean the person is - they don't correlate.