I have a 3-day trip to Paris in early December.

This is not the first time I visit the city. I've already seen most of the landmarks and been to 11 museums (Louvre, Orsay, Rodin, Orangerie, Pompidou, Musée du Moyen Age, Carnavalet, Musée de l'Armée, Arts Décoratifs, Picasso, Victor Hugo)

1.Where should I visit next? I enjoy just being in Paris and walking its streets, but a new museum or two won't hurt.
2.What are the best areas to check out the Christmas decorations besides Lafayette?

Louis Vuitton foundation designed by Frank Gehry. http://www.fondationlouisvuitton.fr/...fondation.html

If you care for Impressionist art and Monet, I highly recommend getting to the Museum Marmottan Monet this time.

I second Musee Marmottan. Have you been to St Denis?

Printemps and Galleries Lafayette definitely have the best windows re: Christmas decorations. Some of the high end shopping areas also have some nice decorations (ave Montaigne, Place Vendome and rue St Honore). I find the decorations in Paris more understated than what we have in the US but so many of the small shops have lovely windows. The Ritz has reopened and a lap through there might be worth while. We always like to pop into George's V to see how they decorate. A glass of Champs in Galleries Lafayette will give you a nice view of their tree under the dome. The tree decor changes every year. The Champs Élysées usually has lights and Christmas market stalls.

Musée Jaquemart-André. Lunch at La Maison Fournaise on the Ile des Impressionistes and a visit to the small museum there.

I'm sure Loacker won't like St Denis. The cathedral is in the suburb, and honestly, St Denis, 'ca craint'. Pay attention to your belongings if you there.

I love Arts-et-Metiers museum:

http://en.parismuseumpass.com/musee-...metiers-15.htm

See Focault's original pendulum swinging and other old scientific artifacts.

yeah, Arts et Metier is something different and it is interesting. I also like the Maillol art museum and the postal museum, and the resistance museum which is quite good for history. SO depends what the goal is -- art or something else.

Jacquemart Andre and Nissim Camondo are both good as a mix of art and objects or decorative art, also. The small Montmartre museum and the Vie Romantique are pretty well done. The Grand Palais often has quite good special exhibits, also.

I think one has to decide one's own interests for the most part on this score. Just get an entertainment guide and you can see them all, as well as special exhibits (Pariscope or l'Officiel des Spectacles).

Yes, not interested in the gritty suburbs like St-Denis. I don't wanna go all the way to Paris to see a place that doesn't feel or look like Paris.

OK. St Denis is one of the most evocative historic buildings I've visited in my life. Once you're inside the entrance, it has nothing to do with a gritty suburb. Not trying to convince you to go there, but adding this for another visitor who may be dissuaded from seeing something remarkable.

Fair enough but we didn't find it that gritty. It's the burial place of French kings and for us, worth the Metro trip. Your loss if you miss it, Paris is quite a diverse city.

You might also enjoy a concert in St. Chappelle. We have booked a holiday concert just before New Year's.

I have not been to St. Denis yet, but hope to do it on this trip. I have always wanted to visit for its historical value.

Thanks for the tips. I might end up going to St Denis, if time permits.

I'm planning to rent an apartment. So, in light of the recent illegal apartments crisis, do you recommend I book one through Booking.com?

You know, I like FlipKey's policies. I called them on the phone, and they were easy to reach and had very good guarantees.

Another vote for the Musée de la Vie Romantique

and a few more out of many not mentioned so far:

Petit Palais

also at Parc Monceau
Musée Cernuschi

Musée Bourdelle

Fondation Cartier

As suggested above invest in the weekly Pariscope or l'Officiel des Spectacles and go from there. They are available at kiosks from Wednesday noon.