North Rhine-Westphalia’s state pollution control law says: Von 22 bis 6 Uhr sind Betätigungen verboten, welche die Nachtruhe zu stören geeignet sind. From 10 p.m. to 6 a.m., activities that could disturb the night’s rest are forbidden. The city of Dortmund reminds residents that there is no legal right to a loud party, in the house or in the garden.