Isidor's house is about 2 mins walk from the Gentilly metro station, which is on the RER B line, so easy to reach from CDG airport and with access to the main metro network. It's a quiet enough street, with only a small amount of noise from the railway, a supermarket nearby, a nice bakery, a grocery store on the corner, and a few restaurants dotted about. It also has A/C and a balcony which were useful in the warm evenings. The wifi worked. And it was clean and comfortable.
The rooms we were given were good. Isidor appears to have moved into the attic allowing him to let out the rest of the house. He normally shares the living and kitchen areas with guests - but he and his folks were away, which meant that we had the whole place to ourselves, which was great, but a little weird as the house is still very clearly 'their' home.
The kitchen equipment, and some of the furniture and plumbing are a bit tired, but everything worked well enough for us to cook and eat and use, and we found the house to be a well positioned, comfortable, good base from which to explore Paris.