Nancy's cuisine is solidly Lorraine: quiche lorraine (the original version, made with cream and lardons but no cheese), potée lorraine (a slow-cooked pork and vegetable stew), tarte aux mirabelles (plum tart), and macarons, which were invented here by Carmelite nuns in the 17th century and are still made at a handful of bakeries to a slightly different recipe than the Parisian version.
The best restaurant area is around rue des Maréchaux and the Vieille Ville streets east of Place Stanislas. The market hall and its surroundings also have good brasseries serving traditional Lorraine cooking at reasonable prices.