German here: you are not allowed to install anything thats visible from the outside without the owners aproval (70% of people Rent in Germany) or even the aproval of the Apartment Owner Association (Imagine HOA but for Apartments and every bit as dumb)
Person living in Germany here: everyone does it anyway, if it's a temporary installation.
So then in Europe you are just as banned from installing an AC unit as I was here in the states in a rented apartment.
Hint: that's not "It's banned in Europe", that's "Landlords generally suck in any possible way"
German here: 53% of the Germans lives in a rented home.
Source: https://ec.europa.eu/eurostat/web/products-eurostat-news/w/d...