I really recommend Natasha. Her flat is small, but cozy and has everything you need. The location is just about three stations away from Sagrada Familia and there are plenty of shops, bars, and restaurants nearby where locals go. There is even a Lidl 5-minute walk away. Natasha speaks Spanish and Russian but is often smiling and has a very positive mind. I barely speak either of the languages but she was trying hard to explain everything. She also has a black cat. The neighborhood is calm and there is a metro station just around the corner. If I visit Barcelona next time, I will stay at Natasha's place again.