Lyon have cancelled more than 1,000 tickets bought by West Ham fans outside the away section for Thursday night's Europa League clash.
The French side host the Hammers in the second leg of their quarter final after drawing 1-1 at the London Stadium last week.
More than 1,000 West Ham fans reportedly bought tickets outside of the 2,816 seats dedicated to the visitors' section for the crunch game this week.
Last week, local police authorities issued a decree banning West Ham fans without a ticket bought from the Hammers' away allocation from entering the Parc Olympique Lyonnais or the area around it on Thursday, April 14 from 8am to midnight.