First of all, you have to know that you rent an apartment from a company, not from a private owner. We've exchanged messages with three different people...
The biggest problem during all our stay was the noise coming from the neighbors, all evening long, as soon as they were there. We've mentioned this to Manuela (our main contact), she replied that they had three little kids and that was it. When the ad says that the apartment is super quiet, that's an issue.
Some equipment was missing too (no TV for instance), the main toilets were broken (someone else mentioned it before) and there was an awful humidity smell in the main bathroom. Last but not least, it's mentioned in the ad that they can keep your luggage when leaving but it's not for free and not that close to the apartment (15 minutes walking distance).
That said, the location is very convenient (close to the metro and the historical centre) but we wouldn't come back.