Katarina is a great host!
My sister and I staid at her apartment for 8 days. Even though we booked the apartment last minute and Katarina was not in Barcelona during our stay, she managed to organize everything for us.
Through her warm welcome, we felt as going to a friend. She prepared breakfast for us and gave us tips about places and restaurants worth visiting / going to in Barcelona.

The apartment is clean and as others wrote, it is exactly as described and as the pictures look like.

Her apartment is close to all the major attractions: Montjuïc Castle, Rambla, Plaza Espanya and the beach.
As the apartment is near the park, even though it is central, it is quiet.

I recommend staying at Katarina's apartment.