Foreign Minister Julie Bishop has confirmed three Australians have been injured in Nice where a truck crashed into Bastille Day crowds, killing at least 60, and has been labelled as a "cruel attack" by Australia's Governor-General.
The three involved suffered minor injuries when attempting to flee the scene, according to Bishop.
"I have just spoken with our ambassador in Paris, Stephen Brady, and we understand that three Australians have been injured," she said, according to the Daily Telegraph.
"They have suffered minor injuries, seeking to flee the scene, to get away from the scene. We are working to provide consular assistance to all three."
In a statement, Bishop said the Australian government condemns the attack and stands by the people of France, the victims and their families.
Earlier in the day his excellency Peter Cosgrove was in Paris to watch Australian Defence Force soldiers take part in Bastille Day celebrations and said he was in "shock" to hear of the attack during a fireworks display.
"We are in shock tonight in Paris as we learn about the tragic events unfolding in Nice," Cosgrove said on Facebook.
"On a day where Australians marched alongside their French counterparts this cruel attack has struck innocents celebrating their national day."
In his first public statement since the attack, French Prime Minister Manuel Valls declared the country would have three days of mourning between July 16 and July 18.
"France is a great country and a great democracy that will not allow itself to be destabilised," he said.
"France will not give in to the terrorist threat, times have changed and France should learn to live with terrorism."
Bishop said travel advice for France was revised to reflect the attack, but the overall level of advice has not changed.
"We continue to advise Australians to exercise a high degree of caution in France," Bishop said in a statement.
"Australians in Nice should remain attentive to their surroundings, avoid affected areas and follow the instructions of local authorities."
Australian Bridget de Jong told the Today Show she was at the Bastille Day Fireworks near the incident.
"We saw people running towards us along the promenade saying don't go back there, there's been an accident, there's been a shooting," she told the Today Show.
"We've seen bodies on the street and we're in a side street and not sure where to go."
Greens leader Richard Di Natale called the attack "another shocking act of violence towards their peaceful country".
"This horrendous crime occurs at a time when the world is still reeling from the senseless acts of violence in Istanbul and Dallas," Di Natale said in a statement.
"In the face of attacks like this we must strengthen our commitment to peaceful democracy, respect for diversity and building cohesion in our global community."
In Sydney, the French flag was raised above the Sydney Harbour Bridge, a candlelight vigil was held outside of Customs House and NSW Premier Mike Baird said he stood by the people of Nice against the evil of terrorism.
If you're unable to contact family or friends in Nice, contact the 24 hour Consular Emergency Centre on 1300 555 135 or +61 2 6261 3305 if calling from overseas.