The 18-year-old turned himself in Wednesday evening.
The Danish editor who ran satirical cartoons about Islam pleads for tolerance.
Stephane Charbonnier was on a 'hit list' that first appeared in an al-Qaeda magazine.
There were several isolated incidents of violence last night, but no injuries were reported.
The leader of far-right party Front National has said she would offer the French population a referendum on the issue.
There have been reports that the gunmen held up a petrol station in northern France Thursday morning.
Tommy Robinson endorsed German anti-Islam marches and said former EDL members have joined them
A 27-year-old policewoman was killed in Thursday's attack
The youngest of three French nationals being sought by police turned himself in
2015 has gotten off to a tragic start for journalists, with multiple killings.
Depictions of the Prophet Muhammad are controversial in many parts of the Muslim world.
Two officers were shot during the attack, one of them at a distance as the gunmen fled.
The magazine lost 10 staffers in the terrorist attack.
It's long past time for Muslims to articulate a political Islam that respects and welcomes free speech.
It's a good time to have a secretary of state fluent in the language once recognized as the lingua franca of international diplomacy.
Police are seeking the gunmen responsible for the deaths of 12 in a shooting attack at the headquarters of Parisian satire magazine Charlie Hebdo.
The organisers of anti-immigration marches across Germany seized on the terrorist attack in Paris
The magazine was firebombed in 2011 after publishing a cartoon of the Prophet Muhammed
Cartoonists mourn their colleagues and rally for freedom of the press.
Jyllands-Posten published 12 cartoons by various artists in September 2005, most of which depict the Prophet Mohammad
Ten journalists and two policemen were killed Wednesday in a terrorist attack by gunmen on the satirical weekly Charlie Hebdo.