From some of the rooms you can see the Eiffel Tower from bed, and while the rooms are small (ALL hotel rooms in Paris are small unless you spend big $,) they are clean and the staff is really kind. The location is very central to many things youll want to see and the Le Tour-Maubourg Metro station is close by. The Metro system is fantastic and easily navigated, especially if you download an app for it.
I would highly recommend Sainte Chappelle on the Ile de la Cite - Notre Dame is cool and all (and on the same island in the Seine River) but Sainte Chappelle is literally breathtaking. Also, the Palais Garnier, the opera house that inspired The Phantom of the Opera has to be experienced. Napoleons tomb in Le Hotel des Invalides really gives you a feel for what a heavy cat he was in French history and theres an excellent military museum there if youre into that kind of thing. The Rodin Museum is right around the corner if you care to stand before the Gates of Hell and do some thinking.
An unexpected delight for us was a picnic lunch in the Jardin du Luxembourg, where Parisians go to escape the tourists. Also, I could spend the rest of my life happily watching the madness that is Paris traffic from atop the Arc de Triomphe, and the view in all directions really gives a sense of the layout and scale of Paris. I can think of a hundred other delightful places there but those are ones I will definitely return to see again. Art museums - The Louvre, of course, but be prepared to be overwhelmed, the Musee dOrsay to stand in front of a Van Gogh and see color like he did, the Pompidou to catch up with the crazy modernists, and the LOrangerie if youre into water lillies and such.
If an overnight trip is in order, I would head West to visit Mont Saint-Michel before I thought of going to another country. I guess it depends on how much time you are going to be there, but thats another place I want to revisit before I die. DEFINITELY learn a leetle bit of French before you go - the simplest greeting in their native tongue will open the door to remarkable hospitality, while failure to do so will be met with the cold aloofness for which they are famous.
Excited for you! You can leave Paris, but Paris never leaves you.