This is the second time we have stayed at Guilaine's apartment. We love the apartment and the neighborhood, and we especially like that this is not a touristy area. Having been to Paris a number of times, we don't feel the need to be in the thick of tourist sites, and we don't mind taking a good walk if we want to get to them.
The neighborhood features top-notch restaurants (both fancy and not), good bakeries, and several wonderful parks for walks. As others have mentioned in their reviews, there are a number of stairs up to the apartment, and stairs from the main floor down to the bedroom. (This is not a problem for us.)
The apartment is modern, with very high ceilings and wonderful windows and light. The kitchen is well-equipped. Note that the shower is hand-held, not the typical wall-mount shower that many Americans might expect. (This, too, is not a problem for us.)
Guilaine is a designer, and her good taste shows. She is also very welcoming and kind. We expect to return!