Daniel’s place was extremely central, near RER, Metro lines 3, 12, 13, 14 ( Saint Lazare being the nearest metro station), and buses 26, 43, etc. Gare du Nord is a 10 minute taxi ride away, the fare will cost around 10 euros. You’re also within a few blocks of Opera Garnier, and Haussmann department stores like Printemps (just walk straight down havre caumartin) and Galerie Lafayette.
Susana was very nice and helpful with all of our needs. We were able to text her during our stay such as when we asked for toiletries. We communicated to Daniel via Airbnb messaging and he was always quick with responding. The car garage in the building had an unfortunate flooding incident during our stay and the elevator had to be shut down. The apartment is on the 5th floor, we asked Daniel about the luggage being carried down 5 flights of stairs and Susana was so kind in helping us with the luggage.
The building itself is very secure, with locked ground floor entry and a 24 hour security guard (and guard doggies to boot). A lot of older folks live in the building. The apartment itself faces the inner courtyard and is very quiet, good for resting. Beds are comfy, we put a duvet over the sofa bed mattress so it was quite comfy. All in all, I would stay here again!