In raids across Germany, 25 people were apprehended on suspicion of plotting to overthrow the government.
According to reports in Germany, a group of far-right and ex-military figures planned to storm the Reichstag and seize power.
A German man named Heinrich XIII, 71, is reported to have played a key role in their plans.
According to federal prosecutors, two alleged ringleaders were among those arrested in 11 German states.
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.
“We don’t yet have a name for this group,” said a spokeswoman for the federal prosecutor’s office.