German authorities on Tuesday launched multiple raids against an extremist network and dissolved the so-called "Kingdom of Germany", the interior ministry said.
The Federal Prosecutor's Office also announced the arrest of four people during the raids, including three founding members of the group.
Described as "dangerous extremists" by the ministry, the Kingdom of Germany is part of the German conspiracy movement known as the "Citizens of the Reich", which rejects the legitimacy of the modern German republic.
Its members believe in the continued existence of the pre-World War I German Reich.
The ministry declared the dissolution of the group, which was accused of "attacking the liberal democratic order".
Raids were launched in seven regions targeting the group, which has approximately 6,000 supporters.
Authorities said its adherents "deny the existence of the Federal Republic of Germany and reject its legal system".
The ministry said the group was banned because "its objectives and activities are contrary to criminal law and run counter to the constitutional order".
They said that over the past 10 years, the group had established "pseudo-state structures and institutions", including its own currency, identity papers and insurance system.