An old friend dines at this place every time he goes to Paris and swears by it. Is it worth it? How is the food?
Food is very traditional and excellent; reservations are hard to come by, unless you are a "regular". Low ceilings and lack of decent ventilation make this place a smoker's paradise. Hopefully the new law will be observed here.
It is definitely worth it. There are two dining rooms with different cartes. The one on the corner of the Quai Voltaire and (I think) rue des Sts.-Peres is the more more reasonably priced one. The oeuf mayonnaise is especially good, and a bargain--just a couple of euros. The steak tartare is also good, as is the Parmentier. The other side is a formal restaurant and is more pricey. If you arrive before 13:00 you should be able to get a table in the low-ceilinged (cheaper) room. They do not accept credit cards, by the way, at least not in that dining room.