We had a wonderful stay at Carol's beautful apartment in the Marais district. It was exactly as described online.
We had no trouble finding our way and getting access to the property.
The steps to the 4th floor (no elevator) turned out to be easier than we expected, and good training for Paris.
The location is fantastic, with lots of lovely small shops, restaurants, bistros and within easy walking distance of many Paris sights. The metro is also nearby.
Carol was not physically present, but she was always available by email and responded instantly with advice and good wishes. She also provided a wonderful book with information about almost anything a Paris newbie could ask for.