We were 5 - 2 adults and 3 children under 12 - staying 3 nights in Danielle's apartment in September. All 5 of us loved the apartment. It is on the 2nd floor of an old building, which is well-kept and calm, with the usual small lift in what would have been the stair-well. Everywhere in the apartment is spotlessly clean. Everything is very well-organised, everything works and the kitchen is extremely well equipped. All the beds are comfortable, including the sofa bed which opens out into a nice double bed with a firm, comfortable mattress. As the building is old, be prepared for some slight creaking in the wooden floors!
We also loved the location. It is on a quiet street in a wonderful area, far enough away from tourist sites to be authentically French, but close enough to those sites, particularly the Sacre Coeur and the Place du Tertre, for easy access. Excellent & varied shops (+ boulangerie!), restaurants and 2 metro lines all within very easy walking distance, with supermarket literally on the other side of the street.
Check-in and communication with Danielle were excellent, with Danielle responding very promptly to all my queries.
We've stayed in many different places in Paris. This apartment will be our 1st choice for our next visit.