We spent a great weekend at Celina's flat! It's very well located - in between Ipanema and Copacabana and also a few minutes from the tube.
The flat is very comfortable (we were in three), cute and the hammock is a huge win in the end of the day.
The building is secure with a concierge 24h and even thou we didn't meet Celina or Maria, the check in and contact with them was very easy.
I highly recommend their flat!