Floats decorated with fresh flowers accompanied by dancers and musicians made their way through the city centre.
The traditional “battle of the flowers” – where fresh flowers are thrown into the crowds – was the first of several processions in the carnival, which is scheduled to last until February 25.
Some 600,000 visitors are expected in the city during the two weeks of festivities, which boast of being one of the largest carnivals in the world.
More than 1,000 singers and dancers from around the world will take part in the carnival, according to its official website.
Unlike previous years, the carnival zone is inland, avoiding the Promenade des Anglais where 31-year-old Tunisian-born Mohamed Lahouaiej Bouhlel ploughed a truck into crowds celebrating Bastille Day last July.
Tourism in the area dropped sharply in the months following the attack – which was claimed by the Islamic State (IS) group – but rose again towards the end of the year, according to the local tourist office.
France has suffered a number of deadly terrorist attacks over the last two years.
Some 130 people were killed in a night of coordinated attacks in Paris in November 2015, also claimed by Islamic State.
On Friday, anti-terrorism investigators detained four people in the southern town of Montpellier.
Initial evidence indicated that the arrests had foiled an imminent plan for an attack, authorities said.
