This is false.

The Kammergericht Berlin (uppermost criminal court for Berlin) has ruled the reasoning of the lower instance why this phrase is not an illegal slogan was not sufficient and there were mistakes in the judgement. It has reopened the case and given it back to the same instance to re-evaluate.

There seem to be two main points:

2. The fact that a slogan is older than the terrorist organization does not preclude its classification as a distinguishing mark if the organization has adopted the already common phrase in such a way that it at least also appears as its distinguishing mark.

4. In principle, the grounds for the judgment must indicate the field of expertise of the expert consulted. If the academic training and even the area of activity in which the expert usually works remain unclear, this constitutes a factual and legal error in the judgment.

There are a couple more minor points from the full reasoning. For example, apparently the court argued even if the phrase were illegal, since the defendant claimed to be an opponent of Hamas they used the parole to display this opposition (analogous to reclaiming slurs) - but the court didn't require the defendant to demonstrate/elaborate on this opposition.

Here's the full decision, in German

https://gesetze.berlin.de/bsbe/document/NJRE001632041

The court has very much NOT ruled about the (il)legality of the phrase. Only that the lower court's reasoning was shit.