The communication / checkin was a bit bumpy though, as the previous guest had lost the keys, so we were not able to get our own. The building's staff just opened us the door and told us to calll the agency, where nobody knew anything and it took several hours to figure it out.
In the end the building's staff was opening us the door with the master key every time we wanted to get in, which was not ideal as we were not comfortable having full access to the apartment with all our belongings in (in a country where English is not very common), and as we always had to wait for somebody to open the door.
But the apartment itself was very nice (super comfortable beds!), very well located and nicely decorated.