In 48 hours of questioning police failed to find proof that the 40-year-old heavy metal musician was planning violence.
His French wife, Marie Cachet, who was arrested along with Vikernes on Tuesday morning, was released on Wednesday evening.
Cachet’s legal purchase of five rifles sparked the arrest, which was ordered by the Paris-based national anti-terrorist police brigade.
Vikernes’s lawyer, Julien Freyssinet, declared the detention “disproportionate” and explained the couple had bought the guns because they are survivalists, who believe that it is necessary to prepare for an impending catastrophe.
“There was a sufficient range of clues and elements to justify the arrests and detentions,” said interior ministry spokesperson Pierre-Henry Brandet, stressing that the action was “preventive”.
Vikernes, who served 15 years in Norway for stabbing a guitarist 23 times, is to be prosecuted for publishing anti-Semitic and xenophobic content on the internet.
He came to live in the Corrèze region of France after marrying Cachet, praising the French countryside’s authenticity.
“Your countryside is beautiful but only because they have not yet been affected by the mass of immigration,” he wrote last year in an appeal to vote for Front National presidential candidate Marine Le Pen.