People hold placards reading in French 'I am Charlie' during a gathering in front of the prefecture in Lille, northern France, on January 7, 2015, following an attack by unknown gunmen on the offices of satirical weekly Charlie Hebdo. Heavily armed men shouting 'Allahu Akbar' stormed the Paris headquarters of a satirical weekly on January 7, killing 12 people in cold blood in the worst attack in F