Breivik, who says his long isolation in prison is a violation of his human rights, has exhausted all of his legal options in Norway. The country's highest court, the Supreme Court, refused to hear his appeal in early June.
His lawyer Øystein Storrvik has therefore taken the case to the Strasbourg court, arguing that the Norwegian state ought to be found guilty of violating the European Convention on Human Rights, which prohibits “inhumane” and “degrading” treatment and guarantees the right to privacy and correspondence.
The appeal, which focuses primarily on the question of isolation, was sent on Thursday, Storrvik told AFP.
The Norwegian state has rejected Breivik's claims, insisting that he has been treated as a “VIP inmate” with three well-equipped cells and regular contacts with prison officials, his lawyer and a prison-appointed visitor.
The now 38-year-old inmate, who earlier this month legally changed his name to Fjotolf Hansen, is serving a 21-year prison sentence that can be extended indefinitely.
In July 2011 Breivik, disguised as a police officer, tracked and gunned down 69 people, most of them teenagers, at a Labour Party youth camp on the island of Utøya, shortly after killing eight people in a bombing outside a government building in Oslo.
He has never expressed any remorse for committing the worst atrocity in Norway's post-war history. He said he killed his victims because they embraced multiculturalism.