This place was ideal for exploring Paris. A bakery on the doorstep started the day well and a Metro right outside meant we could travel anywhere if needs be. However, being quite close to the City centre meant we walked most of the time.
The apartment itself was exactly as you described and was perfect for our trip. It was clean and comfortable.
The Hosts were excellent, answering all our questions and were able to be flexible with checking in and out due to our train times.
The warning about the three flights of stairs was good, as we were prepared and as a location for exploring Paris, we couldn't fault it.