How long does it take to get a reply to your PhD application email in Germany?
Usually, in Germany you get an answer even if it says that you don't get the position. I wouldn't worry if it takes a few weeks which (depending on the institute) can be absolutely normal. You also have to consider that there maybe is a deadline (in German often: Bewerbungsschluss). Normally you get notice a few weeks after that.

It is also absolutely acceptable to write a mail asking for the status of the application (after a few weeks). You also have to consider that currently there are semester breaks in Germany so the professor can be on vacation not reading any mails.