I spent a couple of days in Barcelona and took the time to check out the CoS.
1. C. Dos De Maig 310. (nearest subway station: Hospital de St Pau).
http://scientology-barcelona.org/
One shop window. When I walked by, one woman was sitting in the door talking to another woman. The other woman left and after taking some pictures I walked in and a short dark haired woman asked me to excuse the messs because they were redecorating or renovating or something like that. Boxes on the floor. She asked if I knew anything about Dianetics or Scientology but we didn't get to talk much because the phone rang. After she hung up, she went into the back and I left.
It does not seem to be a very busy place, but she seemed to talk to the person on the phone about some course.
2. Pge. Domingo 11-13
http://www.dianeticabarcelona.org/
I didn't know about this place before I found a business card with its address in the first place I visited. This place had a sign about the personality test. It seemed dark inside so I assumed it was closed and didn't check if the door was open.
I'll try to post some pictures soon.