Hooded gunmen stormed the Paris offices of a weekly satirical magazine known for lampooning Islam and other religions, shooting dead at least 12 people, including two police officers and eight journalists.
Four well-known cartoonists were among the Charlie Hebdo staff killed in the attack, including the paper's editor Stephane Charbonnier, known as 'Charb'.
Across Europe, thousands of people joined candlelight vigils to remember the dead.