Hungarian fans and police forces scuffled in Marseille's stadium on Saturday ahead of a Euro 2016 Iceland v Hungary match.
A Reuters witness saw police officers enter the stands in the Stade Velodrome.
Euro 2016 has been marred by violence, especially in Marseille last weekend when Russian fans confronted English supporters before, during and after the Russia v England game.
Image: Police before the Euro game between Hungary and Iceland in Marseille on Saturday
Photograph: Eddie Keogh Livepic/Reuters