When a Nice airport worker saw a truck thundering past him on the city's promenade, crushing pedestrians in its path, he did not join the fleeing crowds but instead gave chase on his scooter.

After amateur video footage of a man on a scooter speeding alongside the truck went viral, many thought the heroic figure who tried to stop the July 14 carnage was dead.

The man, however, has been found alive and well with only a few minor injuries by Nice Matin newspaper.

Named only as Franck, he told the newspaper he had been willing to die to stop the rampaging vehicle, which crushed 84 people to death.

He and his wife had planned on watching the Bastille Day fireworks display, but arrived too late and were just heading off on his scooter to grab an ice cream when they realised something was amiss.

"We heard shouting and cars reversing. My wife said 'stop something is not right'. We saw the crowd running in all directions, as if they were fleeing something. That is when we saw the truck coming," he told the newspaper.

"He overtook me, driving on the pavement. I can still see the bodies flying everywhere. I immediately understood. I decided to accelerate. My wife pulled my arm and asked me where I was going. I stopped, told her to get off, and accelerated as fast as I could."

Franck, who is in his fifties, said he was "in a trance, but lucid" as he raced after the truck, which was zigzagging between the road and the sidewalk, mowing down people in its path.

When he caught up with attacker Mohamed Lahouaiej Bouhlel, Franck said he decided to launch his scooter at the vehicle, fell and then ran after the truck.

Video footage shows the scooter falling alongside the truck, with the driver running after it and grabbing onto the door of the cab, before falling out of view.

"I didn't know what I was doing, I managed to hang on to the door," he said.

- Pistol-whipped -
The driver's window was open and Franck, who was standing on the step used it to climb into the truck, found himself face-to-face with Bouhlel.

"I hit him again and again, with all my force," he claimed.

Franck said Bouhlel grabbed his pistol and aimed it at him, but that it didn't appear to work.

Bouhlel later used the pistol to shoot at police in an exchange of fire in which he was killed.

"I was ready to die to stop him. He hit me with the butt of the gun and I fell off the step," he said.

Franck escaped with a broken rib and several smaller injuries.

He was not the only one to try and stop the carnage. A cyclist named Alexandre also at one point caught onto the handle of the door, only letting go after finding himself staring down the barrel of Bouhlel's gun.