It is not that easy. Further details are always regulated by law. The federal “Versamlungsgesetz" (Gatherings Act) applies unless individual federal states have passed their own laws.

Outdoor demonstrations must be registered. They can be banned if they directly endanger public safety and order.

In Germany, several demonstrations have been banned in recent days because there were anti-Semitic statements and calls for violence in advance. The police also had to intervene when Israeli flags were stolen and burned. The police will always intervene if crimes are committed during a demonstration. E.g. throwing dangerous objects, causing serious damage to property, etc.

And public support for crimes is not covered by freedom of assembly in Germany.