An inviting apartment in a charming older building, with large windows to leave the light in and old hardwood floors (a bit creaky - I loved these, and I don't think one needs to be concerned about the downstairs neighbours, as we didn't hear anything from the neighbours above). The stone walls keep the apartment cool during the day if you remember to close the light curtains and/or shutters, so it was very sleeping temperatures at night.
Since it's an older building, the stairwell carries sound quite well during "rush hour" and you might hear when the water is going in the other apartments, for us none of this was an issue at all. There's some minor tear and wear, but it's nothing that you wouldn't expect in a private home in an old structure.
The kitchen is complete with a good gas stove stop, an amazing (read: lightning fast) oven, microwave, kettle and coffee machine. Enough pots and pans to stay in and cook.
We were 4 adults, meaning two slept on the couch, which was perfectly comfortable. There's also a beamer and a pretty good sound system to watch movies on. Wi-Fi was fast enough to stream movies from Amazon and Netflix in HD.
Location in Llevalois-Perret was a highlight for us, as it's a neighbourhood with everything you'll need just outside Paris. There's bakeries, restaurants and bistros on every corner and the many shops and boutiques invite to take a walk around the area. There's several supermarkets within 5 minutes of the apartment, and if you're looking for a discounter (Lidl) it's about a 15 minute walk (it does pay off). We walked about 20 minutes to the nearest mall. All in all, you'll get all of the advantages of being in the city, with none of the disadvantages (in our eyes). It's lively but not crowded or noisy, and it's not all catered towards tourism.
The area was also a great starting point to walk to some of the tourist attractions, and I suppose it would be just as easy to take a bus or metro to those areas. In one day, we walked to Montmarte (location of the Sacre Coeur), Moulin Rouge and Café des 2 Moulins, Louvre, Arc de Triomphe and Eiffel Tower and took an Uber back. That obviously was a full day trip, but for example the walk from the apartment to just the Eiffel Tower would have been about an hour (less if you're used to walking).
Elizabeth was incredibly helpful both before we traveled and when we arrived. She knows the area and had some great suggestions for cafés and restaurants. Definitely recommended :)