The Europa League game between Lyon and Besiktas was delayed by about 45 minutes on Thursday following crowd disturbances before the kickoff in France.
The game was set to begin just after 9 p.m. local time but was pushed back after some supporters came onto the pitch to escape clashes between other fans at the Parc OL.
Des projectiles et des pétards lancés depuis le haut des tribunes obligent des supporters à se réfugier sur la pelouse... #OLBES pic.twitter.com/xShgpC5HRR
- Olympique Lyonnais (@OL) April 13, 2017
"Projectiles and Fireworks launched from the top of the stands require supporters to seek refuge on the lawn," Lyon tweeted, later adding that the game would still go on.
Lyon president Jean-Michel Aulas then came down to the pitch in an apparent attempt to defuse the situation.
With order eventually restored, the teams and mascots formed a ring around the centre circle in a symbol of unity, while Aulas applauded the fans as the game got set to begin.
The incident comes two days after explosions near Borussia Dortmund's team bus caused their Champions League game with Monaco to be postponed for a day.
UEFA had already increased security measures at its Champions League and Europa League matches this week after the Dortmund attack.
The return game is in Istanbul next Thursday. The Parc OL will host the Europa League final in 2018.