First of all I would like to point out all the good things about the apartment. :-)
The check-in was super easy and Andrè was very friendly, he waited for us for two hours, because our flight got delayed and so we didn't make it in time.
The bathrooms as well as the kitchen were completely new, even containing a dishwasher, which was great. The whole place was extremely tidy and very well located, only a 15 minute walk from Placa d'Espanya. The beds were very comfortable too, although you could see that the interior was a little worn off.
Which leads me to the downsides of the apartment that weren't prominent and in most cases would be easy to fix.
Firstly, the stairs leading to the third floor were more as much as if they would lead to the 5th. Secondly there were cockroaches in the whole building, as well as mould in one of the guest bedrooms and some of the lights didn't work so the bathroom was pretty much pitch black. One minor thing was that two of the dining chairs had their backrest broken.
But it is a good price-quality ratio and we spent a great holiday in Barcelona. :-)