The apartment: located smack in the middle of Paris, a few steps from Notre Dame (the bells will probably be the only noises you hear), and on a high floor with a spectacular view which makes you feel that you are floating above the city. The flat is clean and tidy, and all the essentials are provided (including tea, coffee and biscuits!).
The host: Alain is a wonderful host. He responded immediately to my initial request; was flexible about timing; on my arrival was very charming and welcoming despite a (very) late checkin; and had lots of helpful recommendations for Paris.
Overall: this was a great experience.