The far-right Alternative for Germany (AfD) party is not allowed to demonstrate on Friday evening on the Mannheim market square, where a police officer was stabbed to death a week ago.
The ban follows a decision by the Administrative Court of Baden-Württemberg, the highest administrative court in the southwestern state.
The court upheld an appeal by the city of Mannheim against a decision of the lower administrative court in Karlsruhe, which had given the green light for the demonstration at the scene of the crime.
This demonstration is scheduled for 6:00 PM (4:00 PM GMT) and can now take place on the Paradeplatz, a central square in the center of Mannheim.