The iconic sails of the Sydney Opera House will be lit in red, white and blue on Saturday as Australians express their solidarity with France after a series of bloody attacks, officials said.

New South Wales state Premier Mike Baird said he had also asked for a French flag to fly over the city's famous harbour bridge.

"Turns out, there isn't one in the country that is big enough," he wrote on Facebook. "So, if we can't source one, we are going to make one."

"We mourn with you, and we stand with you, Paris," he said, after gunmen shouting "Allahu akbar" massacred scores of diners and concert-goers across Paris on Friday night.

In a similar tribute, in New York, One World Trade Center, the skyscraper built on the site of the September 11 attacks of 2001, was also illuminated in the French national colours.

Australian Prime Minister Malcolm Turnbull had earlier said that protecting freedom was a global battle after the attacks left more than 120 people dead.

He said it was a battle against those who seek to suppress freedom and seek to assert "some form of religious tyranny; a threat in the name of God but is truthfully the work of the devil".

"In France and Australia, all around the world, we stand shoulder to shoulder with the people of France and with all free peoples in the battle against terrorism," Turnbull said in a statement.