The owner is very flexible, helpful and friendly! It was also easy to do the check in and check out, which was nice in our case (to spend a couple of hours in the city without bags for our last day in Barcelona).
The apartment is situated in the Gothic quarter which is a good starting place to explore the city. The only thing which is important to notice is the noise (people talking loud on the street, motorbikes, etc.). We are not used to it and we had trouble getting a good night of sleep.