It is hard to understate just how great the location of this apartment is. If you're coming from CDG it's a 10 minute walk from Les Halles (where the RER drops you off). It's also nestled in between several other subway lines. You can walk to Place de la Concorde, Notre Dame, and Orsay in under 20 minutes.
The apartment itself is small, but considering how little time you will likely spend there this shouldn't be an issue. It has a small fridge and a stove in a kitchenette, so if you'd rather go to the store than go out to eat you can certainly prepare things from the apartment. The only drawback I found was the shower, which can be a tight fit if you are a tall person. This was a minor inconvenience.
The host, Philippe, was awesome. He was great with communication and answered my questions very quickly. I would definitely recommend staying here if you head to Paris.