We had a great time at Julia's place in Barcelona! It is located just between the Arc de Triomf and Plaza Catalunya, somewhat in the Gotchic Quarter, and very close to a metro station. Julia was very communicative throughout the check-in experience and our stay. The place was a unique sort of studio with a balcony view of the street below in a great location.
I do recommend bringing an eye mask if light bothers you as the bedroom curtains are very thin.
We will note that we choose AirBnbs so that we have a kitchen to prepare breakfast. Just be aware that the kitchen should work for a couple of meals, but if you plan to cook several meals or stay for a week, there are some limitations. All of the pans are non-stick and are severely scratched and damaged, there was just one wooden utensil and a plastic soup spoon, and no other regular cooking utensils, and we never located any kitchen towels. There was a cutting board and a decent knife though! So I wouldn't expect to whip up a pancake breakfast or family brunch while staying here, but some eggs and vegetables and toast would work ok. We often travel with family members with significant allergies and this kitchen would probably not work for them.