The club describes it as an "ambush".
"The club strongly condemns this cowardly and unacceptable attack, which goes against all values that football stands for", writes Lille in a statement ahead of Wednesday evening's match.
The incident occurred on Tuesday evening outside a bar in Bologna. Italian media reports that around 80 people, mostly Bologna fans, attacked – equipped with iron rods and belts – around 30 away supporters.
Local police say that three Lille supporters have been treated for injuries, but have been able to leave the hospital.
