French President Francois Hollande confirmed that the incident at a factory was a "pure terrorist attack.".
Heavily-armed gunmen shouting Islamist slogans stormed the Charlie Hebdo (a satirical newspaper) office in Paris on Wednesday and shot dead 12 people including its editor-in-chief Stephane Charbonnier, known as Charb.
The magazine's controversial cartoons took a below-the-belt jab at every religion, more so against the Islamic faith in the recent decade.
France is mourning the deadliest attack in the country in four decades in which at least 12 people were shot dead by heavily-armed gunmen shouting Islamist slogans at the office of Charlie Hebdo, a controversial satirical magazine, in Paris.