The region of Catalonia has a budget deficit that runs above Spain's average and is also the region with the largest debt outstanding, twice as large as the region behind. From reading the FT, Catalonia is in big trouble, and they had to introduce a tax that taxes bank deposits i.e. double taxing your income. I don't think they are in a very good shape.

I think that's a bit of a stretch, Catalunya is by itself in a huge problems (debt) and is also still a part of Spain, so you can't that simply separate it from the problems of the country.

It's true that Barcelona by itself is probably still doing pretty fine - but I would say that's for different reasons - there's no shortage of people from all over the world coming there to live/work/study, be it Erasmus students or business people (a lot of Germans my experience is telling). That keeps the renting market busy.

On the other hand, 680€ for a three-bed flat in Les Corts? That's insanely cheap, so either the OP found a great opportunity or the prices really dropped down in a last year (or, third possibility: I overvalue the attractiveness of Les Corts)

Of course imagine if Spain still had it's own currency. It would be in the tank making the cost differential significantly more dramatic. Thus attracting more people and more real estate purchases helping to re-start the economy etc.