I think it was just fireworks.
Trying link again;
http://heavy.com/news/2016/07/eiffel-tower-black-smoke-fire-bomb-terrorism-nice-attack/
Pictures from Nice of the truck show the front windshield with many gunshot holes. It would appear that there clearly were gunshots, at the least from the police at the truck driver.
Will John Kerry have the US embassy in France lit up like the colors of the french flag again? will teamobama order our flags to be lowered again?