Let's put it that way: if you only had one day in Paris, I'd advise you to go to L'Avant-Comptoir. It's THAT good, and inexpensive, and iconically French. This is one of the places I always go back to each time I go back home.
L'Avant-Comptoir is an offshoot from more famous "Le Comptoir du Relais". Both are run by French bistro maestro Jean-Yves Camdeborde.
Camdeborde is the godfather of no-fuss modern bistro gastronomy and one of my absolute favourite chefs back home. He was also one of the chef judges on the French version of MasterChef - kind of a gallic version of Gary Mehigan.
This tiny, standing-room-only bar in the heart of vibrant Saint-Germain des Pres is where you go for fabulous wine by the glass and a quick bite to eat (we call it "dejeuner sur le pouce" in French, or 'eating on the thumb'), or for nibbles before lunch or dinner.
They have a fantastic selection of regional charcuterie and 'hors d'oeuvre' - dazzling patrons (lots of regulars, lots of chefs around too) with a French version of Spanish tapas.
Roasted chicken, foie gras skewers, pickles, octopus carpaccio, prawns a la plancha, black pudding macarons - you name it.
One of favourite 'hors d'oeuvre' at L'Avant-Comptoir was a dish of sliced pigs ears and squids - just to die for. Most dishes are inspired by the Basque Country and south west of France, where Camdeborde is from.
Service is really relaxed and nice, and everyone gets to talk to everyone - great vibe! And all the guys behind the counter are really knowledgeable and passionate about the products they serve you.
So tell me, dear reader, where is the ONE place you recommend people visit in your hometown, should they only be there for 24 hours?
L'Avant Comptoir: 3 Carrefour de l'Odeon, 75006 Paris. No phone, no bookings. Open 7/7. Metro: Odeon.