No, German police cannot access encrypted WhatsApp messages.
They specifically state in the introduction of Chat Control act that the reason for the banning end-to-end encrypted communications is that criminals use WhatsApp and police cannot crack the message, hence the Chat Control act. The police cannot crack these messages and they want to read everyone's messages and that's the whole point of making encryption illegal.
If you are unfamiliar with the topic, you can read more about Chat Control and encryption here:
https://edri.org/our-work/chat-control-what-is-actually-goin...
i dont want to be the guy but the law is not about police having acces to private messages. As far as I understood they want to scan content for csam material by hashing. and if positive police geta involved. Or am I wrong? Maybe I misunderstood something.
but this is still somehow breaking encryption.