We stayed at Arnauld's place for a week, and it was everything we needed for our stay! Prior to the trip I was a bit worried since communication wasn't the best (I did receive answers, just not very timely; note that I was also asking some questions weeks prior to the reservation since I was trying to plan and figure out COVID requirements, etc), but communication throughout the stay was excellent. Arnauld was always available via WhatsApp and answered my questions promptly. He was also incredibly friendly!!
As for the apartment, it's exactly as pictured - note that the toilet and shower are in separate rooms (typical in Paris). The bedroom is quite. big in my opinion and had a lot of room/drawers for our clothes. I also found that there were a lot of outlets conveniently placed. Since it's an older building/apartment, the floors are a bit uneven as well as the stairs going up but I never had any issues. I was working a few days from the apartment, and I found the WiFi to be superb. The living room gets a lot of daylight and some nice sunlight during sunset :) The water pressure in the shower was excellent! We were also provided with extra towels which was great, although they were old and appeared a bit worn/dirty they were definitely clean and freshly washed.
Hands down the best thing about this apartment is the location. It is truly in the heart of Le Marais with incredible food a few blocks away, as well as the metro.
I was with my fiance and it was the perfect size for the two of us (actually quite spacious, in my opinion though I come from NY shoebox apartments), but I think the couch in the living room is a pull-out so it could work for a group of 3. I would highly recommend this apartment for solo or groups of two who are traveling to Paris and want to feel more like a local rather than staying near the Eiffel tower or Louvre.