thanks for sharing your question with us.
I did some research to give you a better understanding of what is considered a criminal offence in Germany and found this website by the Bundeskriminalamt:
If you have a look at "PCS 2017- Documents", there's a catalogue of criminal offences that you can download.
A few of the things that are considered criminal offences are for example
- possession of drugs
- damage to property by graffiti
- computer crime
On the last page (p.44) you can also find a short explanation about the levels of each crime.
I hope this information helps and please don't hesitate to contact us with any further questions!