What is a "don't miss" when in Paris during the Christmas season? We will be there for about 5 days end of Nov- Dec 4.
In addition to the"usual suspects" of museums (Louvre, Orsay, Orangerie, Cluny, Marmatton) and sights (Arc de Triomphe roof, Notre Dame, Sainte Chapelle):
if you get a beautiful clear day, take a Seine cruise (bundle up and stand outside) Not so good in the rain.
Christmas markets -- look online for dates and locations. We liked the one at La Defense, but also just walking around looking at lights was fun. Tree at Notre Dame.
The decorations at Galleries Lafayette are spectacular. After dark, the outdoor windows are fabulous, rach decorated differently. Inside, each year there is a different theme for the tree and decor. Am guessing that Bon. Marche will have the same.
Last year there was not a market on the Champs Élysées. I found an app for Vide Greniers and brocantes, local markets varying from great antiques to community garage sale types. They are great for wandering with neat finds.
Expect some grey rainy days. I have not stayed beyond November 23. Warm one day, cool and damp the next. Layers, gloves and a raincoat are suggested. I bought a nice wool hat at a market that kept me cozy and looking chic! I wear-it at home now and is a nice keepsake.