An attempt by Berlin to clamp down on properties being rented out as holiday homes on Internet platforms like Airbnb suffered a setback on Tuesday as a court ruled in landlords' favour.
The administrative court backed the claims of three homeowners, who had sued for the right to rent out their second homes in the German capital to tourists when they weren't themselves staying there.
The same court had in June quashed a legal challenge to the law, which outlaws property owners and tenants from renting out whole apartments or houses for short-term holiday lets.
The ban still effectively prohibits primary residences from being advertised on Airbnb.
Tuesday's decision had been keenly awaited as a further indication of how judges would view the new regulation.
Some landlords even received letters, seen by AFP, indicating that the city was waiting for a legal steer before proceeding against them.
In the case of the three landlords - who live in Rostock in northern Germany, Denmark, and Italy when not in Berlin - "private interest outweighs the public interest" in keeping the properties vacant, the judges said.
Berlin's "wrongful use law", in force since May 1, provides for fines of up to EUR 100,000 ($111,000) for people advertising their homes for Airbnb-style rentals without official authorisation.
Supporters of the law say increasing use of online rental platforms in Berlin - a tourism and party hotspot that draws visitors from all over Europe and beyond - is driving up property prices by taking large numbers of homes off the residential market.
Citizens can even report those they suspect of using an apartment for holiday rentals anonymously via the city government website.
In June 2015, the city also introduced a cap on rent price hikes in a bid to keep residential apartments affordable.