A Norwegian neo-Nazi arrested Tuesday in central France "could be preparing a terrorist act of great magnitude," France Info radio said, citing the Interior Ministry.
RTL radio said earlier that the man in custody, identified as Kristian Vikernes, a sympathizer of Anders Behring Breivik, perpetrator of the attacks that left 77 people dead in Norway in July 2011, was organizing a "massacre."
The investigation is being handled by the Antiterrorist Tribunal in Paris.
Vikernes, who apparently moved to France in 2009 after serving a 21-year sentence in Norway, was arrested in Correze together with his wife, a French citizen.
He was convicted in Norway of stabbing a friend, French media said. EFE