The group of far-right and ex-military figures planned to storm the parliament building, the Reichstag, and seize power, APA reports citing BBC.
A German man referred to as a prince called Heinrich XIII, 71, is alleged to have been central to their plans.
The plotters are said to include members of the extremist Reichsbürger [Citizens of the Reich] movement, which has long been in the sights of German police over violent attacks and racist conspiracy theories. They also refuse to recognise the modern German state.
An estimated 50 men and women are alleged to have been part of the group who are said to have plotted to overthrow the republic and replace it with a new state modelled on the Germany of 1871 - an empire called the Second Reich.
More than 20 people have been arrested in Germany in connection with a right-wing plot to overthrow the government, APA reports citing the National News.
German police launched nationwide raids on Wednesday against members of a "terror group" suspected of planning an attack on parliament, federal prosecutors said in a statement.
Individuals belonging to the "Citizens of the Reich" (Reichsbuerger) movement are suspected of "having made concrete preparations to violently force their way into the German parliament with a small armed group", they said.
In total, 25 suspected members and supporters of a far-right terrorist group were detained in the raids, which were conducted across 11 German federal states, the federal prosecutor's office said.