Heavily armed police on Sunday arrested and searched the home in Strasbourg of a friend of the knifeman who carried out a deadly attack in Paris, AFP journalists at the scene reported.
Police left the home with a man in handcuffs, his face hidden by a hood, wearing a black T-shirt with "Grozny", the capital of Chechnya, on the front and a drawing of a Kalashnikov rifle on the back.
A source close to the case said the young man was the "individual closest" to the Chechen-born Azimov, who went on a stabbing spree in central Paris that left one dead and four wounded. Both were born in 1997.
A laptop was seized in the police raid.
Azimov had lived for several years in Strasbourg, home to a sizeable Chechen community.