A bistro is not a brasserie. The terms are sometimes used interchangeably, or imprecisely, in the U.S., but in France, birthplace of both, they almost always retain their original meanings, and understanding the difference might be useful to the hungry traveler.
Brasseries are Alsatian in origin. The word itself is French for "brewery," and the original brasseries were either attached to beer-making facilities or were owned by them and specialized in the beer they produced. Brasseries are by definition large, open, noisy places; their menus are typically long, and, whatever else they may offer, there are nearly always oysters, soup, and choucroute — and of course beer.
Bistros are small, intimate, low-key. They are often family-owned — monsieur cooks while madame runs the dining room and keeps an eye on the cash register, in most cases, though the reverse is sometimes seen, too — and at least in theory moderately priced. Organ meats (calf's liver, pig's feet, sweetbreads, etc.) are basic to the bistro menu, as are small steaks and roasted chicken, and such homey fare as pâtés and terrines, boeuf bourguignonne, coq au vin, pot au feu, and hachis Parmentier (the French version of cottage or shepherd's pie). The vegetables of choice are pommes frites, white beans, and lentils. Minor wines flow freely.
That's basically all you need to know. If you're the inquisitive type, though, it might occur to you to ask that, if the word "brasserie" originally meant "brewery," what did the word "bistro" originally mean. Good question.