In the Faubourg St Denis area, in the covered market of St Martin, is a little place called au Comptoir de Brice. The chef wanted a casual place with simple, good food (he even calls it “gourmet junk food”) and it is becoming very popular.
If you order a burger you get two of these-like sliders-with the fries and salad. The burger was really good. I saw a type of croque monsieur next to me but it was made of duck and foie gras and looked delicious. The steak looked good too at a pricy 25 euros. So I recommend the food. The seating was a bit uncomfortable and it was a crowded room but fun.