Fans in Nice lose their fucking minds... and almost in a single moment, seem to remember, for a moment, where they are, who they are, and SHIT! we aren't supposed to be here... as if the endorphin hit magically disappeared in a moment and they realize "Oh fuck, I could get banned for life doing this!"
[YOUTUBE]https://www.youtube.com/watch?v=21Om63zZN6E[/YOUTUBE]
The tale is that fans were tossing plastic water bottles at Marseille players and the Marseille players were done with it after the player to take the corner got hit in the back by one. He aimlessly throws the bottle back into the crowd. That got the home fans angry... and then another Marseille player kicks a ball into the crowd, and a small, but hardly not negligible amount of fans pour onto the pitch.
It is one of those moments when fans forget they are attending a fucking football match not anything important.
Marseille would walk out of the game. Football players should never throw or kick things into the fans... though arguably the one player may have been "trying to give the water bottle back".

Kicking the soccer ball was a bad idea. Of course, the refs and stadium staff did nothing regarding the throwing of stuff before the incident, so I imagine Lyon is in trouble for that. In defense of Lyon, some of their players did very well, at their own risk, of trying to keep invaders off the pitch.