Prime Minister Tony Abbott has described the fatal shooting of 12 people at the office of a satirical newspaper in Paris as an "unspeakable atrocity".
Heavily armed men shouting "Allahu Akbar" stormed the French headquarters of Charlie Hedbo on Wednesday, killing a dozen people in what French President Francois Hollande called "undoubtedly a terrorist attack".
The assault sparked a massive man hunt as the two gunmen managed to escape, executing a wounded police officer as they fled.
The weekly newspaper had a history of causing controversy with cartoons of Islam's prophet Mohammed.
In a post on Twitter on Thursday, Mr Abbott labelled the attack an "atrocity".
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"If you don't like something, you don't read it; you don't kill people you disagree with," the tweet said.
The attack comes less than a month after lone gunman Man Haron Monis took 18 people hostage during a deadly siege in a Sydney cafe.
Monis and two of his hostages, Tori Johnson and Katrina Dawson, were killed in the violent conclusion to the siege in the early hours of December 16.
