According to BFM TV, the truck travelled across a distance of about 2 kilometers (1.2 miles) smashing people.
The driver was shot dead by police. According to ID documents found inside the truck, he was a 31-year-old man who was a resident of Nice of Tunisian origin. It is unclear whether he had any accomplices.
Weapons and grenades were found inside of the truck, President of the Regional Council of Provence-Alpes-Côte d'Azur Christian Estrosi said.
Anti-terrorism prosecutors are now investigating the attack.