Great advice above. We did all of the above first week in December. Been to France a dozen plus times for work and enjoyed the relative calm of this time of year. Pre holiday post summer but a bit rainy.
I would add in a small group walking food tour. These can be done at various price points but are a lot of fun and a great way to mix a history lesson, sight seeing and great food and wine.
Of course worth a quick cab ride to Notre Dame to see the repair process might also be of interest…
About an hour outside of Paris is a great horse town Chantilly that is the home of a great hotel (the chateau Chantilly) and a beautiful castle, museum and horse facility that welcomes guests. Their is also a Michelin star restaurant. Beautiful place and if time constrained allows for a great Paris/French country side combo.
Beautiful place!!