The police discovered a large amount of weapons and ammunition in the apartment of a 70-year-old man in the Allermöhe district of Hamburg.
The apartment should be evicted, a police spokeswoman said on Tuesday.
The "Hamburger Abendblatt" had previously reported.
Because of the man's mental health problems, the police arrived on Monday.
Hamburg - According to the information, the man was hoarding firearms and stabbing weapons and various types of ammunition, including hand grenades.
dpa