Do you have a handy link, btw? I did some searching and all I can find is their new "self-determination" law reported by AP[1], and their report doesn't mention deadnaming. The only places I can find saying that deadnaming will be fined are your standard right-wing transphobic nutjobs.

[2] (with an NSFW header image) explains that it only covers "[deadnaming] with the aim of harming the person" which is completely different from "deadnaming [is] a crime", right?

[1] https://apnews.com/article/germany-transgender-legal-registr...

[2] https://euro.dayfr.com/trends/756176.html