Catacombs, Le parc Montsouris butte aux Cailles district, place d’Italie, Chinatown
The Eiffel Tower, Musée de l’Homme, Cité de l’Architecture
Musée du Quai Branly.
Latin Quarter, St Germain des Prés district
Sainte Chapelle, Conciergerie, Musée du Louvre, Musée d’Orsay,
The FIAP Hostel is in one of the best locations. It is a short walk to both the 6 and the 4 metro lines. The staff are very accommodating and allow you to store your bags pre/post check in/out. There is a lot of natural light and the coffee in their little bar area is fantastic. The only problem I had was that the hair dryer didn't work and the outlet in the bathroom was busted, which is only a minor inconvenience and didn't deteriorate my experience. I intend on returning.
Extremely accessible (right next to OrlyBus, and the RER to Charles de Gaulle (aka "Chuck D"). Room was exceptionally clean. No TV, no street noise. Doors have to be slammed to close, so there is a bit of banging in the halls at night.
Security is top notch. Desk is friendly enough. Wifi works, but don't expect to stream videos or anything without paying for the fast wifi.
Drawback: nothing is accessible for the differently-abled. Stairs abound, no elevators