According to reports in the media, French intelligence services acted out of fears he may have been about to carry out a massacre, like the one committed by Breivik in Norway two years ago, when he killed 77 people in a bombing and mass shooting.
Police acted after his French wife, the mother of his three children recently purchased four rifles. The wife has a license to own guns and is a member of a local shooting club but police feared the weapons had been bought for a far more sinister reason.
"That was at the origin of the investigation ... There were several suspicions that made the services fear he could possibly carry out a violent act," an source at the prosecutors office told Reuters news agency.
Officers are currently carrying out a finger tip search of his home to try to find illegal weapons and explosives or any evidence that might back up their suspicions, RTL reports. Vikernes could be held in custody for the next 96 hours, as is allowed under French anti-terror laws.