The National Museum of Natural History is unlike any other I’ve been to. It is fairly worn out but is great. It is displayed in a very different t format to what I’m used to. https://en.m.wikipedia.org/wiki/National_Museum_of_Natural_H...

Quiet and completely excellent, The Museum of Heritage and Architecture. https://www.unjourdeplusaparis.com/en/paris-culture/musee-ci...

The Army Museum is worth a visit - it is interesting to see a less Anglo centric view of the wars, particularly WW1. The paintings are deeply grim - not ideal if you have young kids. https://en.m.wikipedia.org/wiki/Musée_de_l%27Armée

The Museum of the Middle Ages is currently being renovated but is well regarded. https://en.m.wikipedia.org/wiki/Musée_de_Cluny_–_Musée_natio...

Probably a candidate for best museum in the world, the Louvre is a great way to completely waste a day with massive crowds, sore feet, food and water shortages, closed exhibits, intense heat and even more crowds. Get a map ahead of time and check that the things you want to see aren’t closed before you go.

The Pompidou Centre (Centre Georges Pompidou) [1]. It's technically not a single museum, but several, including the largest museum for modern art in Europe (Musée National d'Art Moderne) and IRCAM, which is about music and acoustic research.

If you're into modern art and/or architecture, it's a must-see. The center itself is a beautiful mess of industrial design, and they have everything ranging from modern paintings to furniture to contemporary sculptures to technological inventions.

Two of the current exhibitions are an installation by Ryoji Ikeda [2], which is one of the most superb audiovisual pieces I've seen (you sit in a completely dark room and watch a huge projection) and Coder Le Monde [3], a history of generative art (digital 2D and 3D, as well as physical), computer graphics and visualization. Both are fantastic.

The nearby Palais de Tokyo is also fun, as is the Museum of Modern Art, which is next door to it.

Everyone mentions the Louvre, but it is incredibly crowded and touristy, and the 90% of the paintings are portraits of 19th century nobility. The gardens surrounding the Louvre are much enjoyable than the inside, in my (possibly unpopular) opinion.

[1] https://www.centrepompidou.fr/en

[2] https://www.centrepompidou.fr/cpv/agenda/event.action?param....

[3] https://www.centrepompidou.fr/cpv/agenda/event.action?param....

The ossuary, for sure. Louvre is a meh. The park adjacent to the Louvre is good-to-go. Wander between the Louvre and Eiffel, there is a brassiere frequented by diplomats. Pickup intramural football (soccer) by the nurses' college just across the river. Explore on foot with only a rough plan is usually the best way to find treasures.

Looks like it is currently closed, but from an interesting infrastructure standpoint, the Musée des Égouts de Paris (sewers underneath Paris). https://en.wikipedia.org/wiki/Paris_Sewer_Museum

The Guimet Asiatic art museum is pretty spectacular:

http://www.guimet.fr/

My favorite is La Cité des Sciences, although it's not really a museum but more of an exhibition place for all things related to science.

Used to go there all the time as a kid, especially to read 2600 magazine in the library.

The Louvre must be on any list.