Stay here! The view from the top room is worth the walk up. The space easily accommodated 7 people (more could likely fit if needed). Hervé was an excellent host, greeting us with a bottle of wine, drinks for the kids, fresh fruit and baguettes. He provided outstanding restaurant recommendations (just follow his advice - you’ll be happy). He was incredibly responsive leading up to and throughout the trip.
The location is excellent. The neighborhood is fun to explore, and has a couple of good bakeries to buy your morning croissants. You can walk to the Louvre and it’s a two minute walk to a metro station so you can easily explore Paris. My entire family (65+ year old parents, wife, and children - two 15 year olds and a 6 year old) loved our stay in the apartment - and were fine with the stairs, it’s how we justified eating our morning croissants!