This apartment is in a perfect location for Paris; very near everything one would wish to see and close to transport if required.
The flat is incredibly spacious for a Paris apartment and that was very much appreciated by us( two friends convening on Paris from different timezones and so requiring space to sleep at different times if required).
Caroline was very responsive and explained about the Nuki app which, once understood, is indeed very easy to use.
What I would say though is that Paris is undergoing a lot of construction work (perhaps pre Olympic Games?) and there is a building being renovated right across the street from the apartment so one is very much aware of the construction traffic there from 8am. Also, be aware of the foot noise in the apartment upstairs which did indeed disturb us. If these things don't bother you then you will be fine.