Lille are considering legal action after defender Tiago Santos suffered a serious knee injury following a controversial challenge during their 1-0 Ligue 1 victory over Le Havre on Saturday.
The French club have criticised the tackle by Le Havre midfielder Amir Richardson, describing it as dangerous and uncontrolled, while questioning why the incident did not result in a red card.
Santos, 24, was stretchered off during the first half after suffering a ruptured anterior cruciate ligament (ACL) and a meniscal tear in his right knee.
Despite the severity of the injury, Richardson escaped disciplinary punishment, with the referee awarding only a free-kick for the challenge.
Lille believe the tackle warranted a straight red card and have formally requested that the incident be reviewed by the relevant football authorities.
Lille have called on the French football authorities to examine both the challenge and the decisions made by the match officials.
The club argue that Richardson's tackle was made from behind in an uncontrolled and dangerous manner, placing Santos at significant risk of injury.
In an official statement, Lille expressed serious concerns about the circumstances surrounding the incident and the absence of disciplinary action.
"Beyond the injury itself, the circumstances in which it occurred and the lack of sanction raise serious questions for the club," the statement read.
Lille confirmed that they have referred the matter to the French Football Federation (FFF) and the Professional Football League (LFP), requesting a review of the referee's decision and the involvement of the video assistant referee (VAR).
The club also indicated that it is exploring possible legal remedies, including seeking financial compensation for damages resulting from the injury.
Santos is expected to be sidelined for several months, dealing a significant blow to Lille's defensive options during an important stage of the season.
Le Havre have responded to Lille's accusations by defending the match officials and questioning the possibility of retrospective punishment for Richardson.
The club confirmed that both Richardson and Le Havre had expressed their support for Santos and wished him a successful recovery.
However, Le Havre maintained that the referee and VAR officials had handled the incident appropriately.
They also challenged Lille's attempts to pursue further disciplinary action, arguing that retrospective punishment in these circumstances would fall outside the existing regulations.
"HAC respects all fellow Ligue 1 clubs and expects the same respect in return," Le Havre said in a statement.
The disagreement has intensified scrutiny of the incident, with the two clubs holding opposing views on whether the challenge warranted additional punishment.
BBC Sport has contacted the LFP, which oversees France's professional football leagues, for comment.
The injury comes at a difficult time for Lille, who currently sit second in Ligue 1 and are preparing for a crucial Champions League encounter against Arsenal on Tuesday.
Santos' extended absence will force Lille to adjust their defensive options as they continue competing domestically and in Europe.
The Portuguese defender now faces a lengthy rehabilitation period following the damage to his ACL and meniscus.
Meanwhile, Lille's decision to pursue a formal review could bring further attention to the consistency of refereeing decisions and the handling of dangerous challenges in French football.
With the club considering legal action and Le Havre standing firmly behind the match officials, the dispute remains unresolved.
For Lille, the immediate priority will be supporting Santos through his recovery while seeking answers over a challenge they believe should have resulted in a dismissal.
