We enjoyed our stay at Eric's. We sent him a message when we arrived at Gare De Nore and he arrived as we were walking up the street.
The location can't get much better. You are right across from the Rivoli station to catch the #1 line and about 4 blocks to Les Halles to catch RER and other Metro lines.
We really enjoyed just having the windows open and watching the city. It is loud with the windows open but they do an amazing job cutting down the sound. The noise really wasn't an issue at night.
The only concern I would have about Eric's place is if you have very small children (just walking or crawling). The vintage wood floors in the unit are a mess with separation between planks and warping. I'm sure it is tough to rip up vintage floor but they really need to be replaced. I wouldn't consider them safe if I had a child that crawled or just started walking. The floors were not an issue for my family.
Overall, it is a perfect base for a family stay in Paris.