Didier's apartment was the perfect location for us being either easy walking distance and convenient on the Metro to all of the spots we hit in Paris. More importantly though is that the kitchen is well stocked with a gas stove and stainless countertops, so it is easy to clean and one can cook in a way that that the vast majority of rentals in Paris simply do not allow. We took full advantage of that!
The main living room / dinning area is quite functional and comfortable with large windows along two of its sides allowing for wonderful natural light during the day and very warm lighting at night. While the apartment could certainly accommodate 3 people, I think it is ideal for two traveling as a couple.
It is important to remember that it is in fact someone's home in an older building and as such has some of the quirks that come along with that. Didier's communication was very good and we felt very fortunate that he opened his home to us. We hope to come again!