Books have been written on Paris' museums: the Louvre, the Grand Palais,the Jeu des Paumes; the Picasso Museum; The Rodin Museum; the Museum of Locks; the Museum of Wine. Etc. These are just the ones I find a tad more off-beat and under-visited.
This shouldn't be hard to find - it's right under the open square in front of Notre Dame. But I don't know many people who've actually been to it. Which is too bad.
The museum is basically a gently guided visit to the different layers of Paris which have existed directly in front of Notre Dame. This includes some Gallo-Roman habitations and a medieval street which once went right up to the cathedral.
What is extraordinary about the museum is what it doesn't do- it doesn't outweigh its subject with its presentation. Basically, the original excavations have been left in place, relatively untouched. Beside each one, a scale model shows you more precisely what you're looking at. So you get the information. But you also get the full effect of the raw site.
METROS: Cité, St. Michel.
Curious about the rest of France's architecture? But no time to get beyond Paris? Don't despair. In the Palais De Chaillot (the semi-circular structure across the river from the Eiffel Tower), one of the many museums is this one, which shows large-scale casts of key elements of major monuments from all over France. It's a little as if a New York museum had reproductions of Seattle's needle, St. Louis's parabola, Mt. Rushmore and the Washington monument all in one museum.
UPDATE 2008: Quite confusingly, the museum apparently still has the same name, but is now part of Cité de l'Architecture et du Patrimoine (City of Architecture and Heritage), which also includes modern architectural models and projects. The simplest way to find it is to go into the right entrance as you face the Eiffel Tower.
If you're a lover of design, even if you don't plan to see the museum itself, you might have a coffee in the cafeteria in the lobby, where my hot chocolate was served in a rather unusual plastic set:
METRO: Trocadéro.
LAST UPDATED:February 2009