Carl's place is very clean and he was quick to respond when there was a problem with retrieving the keys from the safe they are kept at. The only things we had problems with in the appartment were the windows which we are not sure you can actually shut and lock and the shower which leaks all the water from the hose, making showering take a bit longer. The appartment is located in close proximity to a metro station and a super market, you can also reach the city centre and multiple bars by foot easily. You should not expect to stay in an upper class part of town, with a hotspot for drug dealers practically on your doorstep. However you can ignore those, they will not be aggressive.