Pierre was very helpful even before I arrived in Paris. His instructions for finding his home were clear.
The location in the 5th arr. couldn't have been better. The RER (regional) train from the CDG airport stops just a couple metro stops away, so it was possible to go to and from the airport easily. If you are coming from the airport, I strongly advise buying a weekly transit pass. It is a bit of a nuisance (you have to have your picture taken, etc.) but it is well worth it in terms of convenience and cost. The pass is called Paris Navigo Decouverte Pass: read about it online before heading to Paris: there are some nuances.
Pierre's is near Les Gobelins, which is a lively area with lots of good restaurants and cafes. Even better, just a couple blocks away, there is a street (no cars) with little shops selling produce, wine, cheese, bread... just about anything you need. I actually bought most of my food on that street and prepared it at Pierre's rather than eating in restaurants.
I was in Paris for work, so I appreciated that Pierre's home had a really good Internet system and a convenient small desk for my laptop. The living room is on the small side, but just fine for two people. The kitchen has all the necessities. I was planning to stay for two weeks (this was cut short by the coronavirus), so I was especially happy to find that the washer and dryer were fully functional, the dishwasher was great to have too. Pierre also provided bottled water and coffee capsules for the coffee machine: there was a nominal charge for these based on the honor system.
The bedroom was very comfortable in every regard, but the best part was how quiet the entire apartment was. It faces into a courtyard, so there was zero traffic noise. The building is old, so people walking around upstairs was noticeable but not bad at all (and a good reminder that there are also people downstairs, so no shoes while in the apartment: besides, the floors are too nice to be scuffed up).
The bottom line is that I had a really pleasant stay, Pierre is very nice and responsive, and the location couldn't be beat. Due to my trip being cut short by the coronavirus, I still owe my wife a trip to Paris and when that time comes, I hope next year, I will try to stay at Pierre's again.