I think, as stupid as it sounds, you HAVE to have one of the hotdogs they serve from little bakeries on the streets. They are served in a baguette with french mustard (which is TDF is you like mustard!) and sometimes have cheese on them. They are soooo good.
Also, make sure you get a Croissant with Jam and butter, and have a beignet-
(I might have spelled it wrong) bascially the most awesome doughnut type thing!
Those are my touristy but delicious favorites! I always bring home a bottle of their french mustard from a supermarket because it is soooo good! Have fun!