An 18-year-old sought by police over the terror attack at satirical weekly magazine Charlie Hebdo has handed himself voluntarily in to police in north-eastern France.
The police declined to identify the man.
Police are hunting for three French nationals, including brothers Said Kouachi and Cherif Kouachi, following the attack that left 12 people dead. The third suspect is a student named Hamyd Mourad.
Local media sources told Reuters that the man had decided to go to the police after seeing his name in social media.
Arrests have also been made of people linked to the two brothers.
The attack at the magazine's headquarters saw the assailants shoot dead 10 journalists including editor-in-chief Stéphane Charbonnier as they stormed into the office shouting "Allahu Akbar" in what is believed to be a revenge attack against the publication that has lampooned religions.
Armed with Kalashnikov rifles and other sophisticated weapons, the gunmen went on the rampage in a pre-planned military style, killing the top cartoonists and two police officers.
President Francois Hollande has promised to deal severely with the perpetrators of the massacre, said to be the worst terrorist attack in France in 50 years.