At least 84 people were killed and dozens others critically injured late on 14 July when a large truck ploughed through a crowd attending the Bastille Day celebrations in the French town of Nice.
President Francois Hollande described it as a "terrorist" attack on revellers watching a Bastille Day fireworks display.
The driver of the truck was shot dead after barrelling two kilometres through the crowd, sending hundreds fleeing in terror and leaving the area strewn with bodies.
The attack comes eight months after Islamic State terrorists attacked Paris nightspots, killing 130 people and dealing a hard blow to tourism in one of the world's top destinations.
According to the media reports, the authorities recovered identity papers belonging to a 31-year-old French-Tunisian citizen in the truck along with guns and "larger weapons."
The 'terrorist nature' of the Nice attack is 'undeniable' President Hollande said in a televised national address, adding ,"state of emergency in France will be extended by three months."
The President confirmed that there were several children among the as families were present at the place celebrate France's national day.
"France was struck on its national day... the symbol of freedom," said the emotional President.
-With agency inputs