Dear Sir or Madam,
the possesion of a weapon, including thrust und cutting is prohibited by german "Waffengesetz".
Section 42 a Waffengesetz stipulates, that the mere possesion is a breach of the law, which leads to a fine.
This does not consitute a crime in the narrower sense of the word, but however a breach of law with a monetary penalty (Section 53 (1) no 21 a Waffengesetz).
A violation of the provisions of the "Waffengesetz" can be sanctioned with a fine up to 10.000 €.
Unfortunately there is little grounds to appeal against this fine.
Not knowing the provisions concerning weapons and such, does not give any legal reason to reject the fine, since a lack of due dilligence is sufficient for a breach of law and to be subject to a fine.
In other words, the breach of law has not to be conducted willingly or knowingly.
To avoid further complications or even a court trial it seems recommendable to pay the fine.