French Montana: Haaaaaaaah-ppy Birthday with All My A-List Friends

French Montana celebrated his bday Tuesday night in the best way possible ... with all of his super famous friends.

French, who turned 31 on Monday, was at 1 OAK in L.A. joined by the likes of Justin Bieber, Amber Rose, Meek Mill, Wiz Khalifa, Keyshia Cole and Chris Brown.

We don't know if there was cake, but we hope they kept it French when it came time to sing "Happy Birthday" ... "Haaaaaaaaaaah!!"