In the small world of political satire, many cartoonists knew the journalists at the French weekly magazine who were among 12 killed by suspected Islamists yesterday.
They expressed their anguish and deep anger at the killings in the way they know best.
One of the pictures that quickly went viral on the Internet was by Dutch artist Ruben L Oppenheimer, showing a plane flying into two pencils standing erect, reminiscent of the Twin Towers in New York.
He admitted the attack "hit a nerve", but said: "Our task is to keep doing what we do... Focus our satire on those in power and those who seek to wield power in ugly ways.