The location of the apartment is wonderful, and the view from the terrace nice - one can see the top part of the Eiffel tower.
The place is small - this is clearly indicated in the description. However it is also cluttered with other people's stuff, so it is even smaller than stated. The duvets/blankets we were provided had no case, and probably had been used like this by other guests before us. The crib for our baby had no mattress and no bed linen. The bathroom was probably just old but had many stains and looked worn out. So in the end after one night we decided to cancel and to move to a hotel.
About two weeks before check-in, we also asked for a slightly change in the reservation (arrival one day later on a six days stay) but this was declined. This is absolutely in the host rights, but in my few airbnb experiences nobody had declined such requests, especially when the cancellation policy for the apartment is moderate.