Sibylle's place is a fully-equipped apartment in a great location in Paris -- in fact, it's the family's main home at other times of the year. So, all the usual amenities were readily available. This made it a great base of operations for exploring Paris.
Communications with Sibylle were super fast and spot-on. We ran into a surprise complication, when our son came down with an infection, and Sibylle helped us find a doctor to come to the house within about 2 hours. That helped a lot in getting our trip back on track.
The unit is on the third floor in a gorgeous historic apartment building. There is an elevator right in front of the door into the unit. Eiffel Tower, grocery store, restaurants and several public transportation options are all within walking distance.
Unfortunately, parking is limited. There are a few spots in the building's courtyard, but while only intended for short-term parking, they were occupied the entire time that we stayed there. Street parking is available in principle, but because of Paris politics is really only is an option for full-time residents. For visitors, it is not only prohibitively expensive, it also only allows a maximum of 6h of parking at a time. Fortunately, we discovered that NeoParking can arrange for very reasonably long-term parking. We ended up parking in an underground garage right next to the Eiffel Tower for less than $10/day. That's an almost 20min walk from the apartment, but since we didn't really need the car in Paris, that's OK.
We stayed in Sibylle's place during a major heatwave with some days pushing up to almost 40°C/104°F. That was decidedly uncomfortable, as many public places have inadequate or no air conditioning. The apartment itself didn't have AC either, but by keeping the windows closed during the day, we were able to keep temperatures tolerable.
Overall, we really enjoyed staying in this place. The downsides listed above were not in any way limited to Sibylle's place, but they are just a natural consequence of looking for a place in the center of Paris.