Au Pied de Cochon, near Les Halles, is open 24 hours a day and hasn't turned their ovens off since about 1948! Reviews are mixed. Certainly there are restaurants in Paris that are better value for money (as well as many more expensive) or where the waiters are more effusive, but not so many where you can have the authentic French restaurant experience in the small hours with a full (not reduced) menu choice! Welcoming, even if you turn up well after midnight after arriving on a late Eurostar or a late plane and checking into your hotel.

The Terminus Nord brasserie, opposite Gare du Nord, is open until 1 am. (Last orders may be before that, but they still take reservations up to at least midnight.) This is a little outside of central Paris but, if you are staying a little further out or if you're up for going "off the beaten path", it would be worth it to check it out.