I stayed two nights in the smaller of the two bedrooms that Catherine provides. The room was clean and well lit. The bed itself is comfortable. The mattress is twin sized, fine for me but perhaps not for a taller person. The temperature was fine in the room (early June), especially when I opened the window and ran the oscillating fan. I stayed over Saturday night; there was some noise from a nearby party, but nothing that jetlag and earplugs couldn't overcome.
There is a shared bathroom down the hall from both bedrooms. Again, it was clean and well-lit, with plenty of towels, soap, lotion, etc. The bathtub has a hand held sprayer, which is typical for European style bathes, rather than a wall-mounted shower head.
Catherine provides breakfast. I had excellent French-press coffee and apple tart. The view from the breakfast table is picturesque, looking out over green space and interesting city views. The living room itself is comfortable, with lots of art and art-related books around the space.
Catherine was accommodating on both checkin and checkout times. I was switching to a hotel, and she offered to let me keep my luggage in the apartment until my hotel room was ready. Despite my inability to speak French, we were able to communicate with few problems. Her place is close to the metro line.
I'd definitely stay again, and highly recommend Catherine's place to other travelers.