Lyon plan to hand down a lifetime ban to one supporter for a Nazi salute that was captured on camera as the club stunned Manchester City in the Champions League.
Wednesday's 2-1 victory over Premier League holders City has now been marred by video footage that spread online following the Group F opener at the Etihad Stadium in Manchester.
Ligue 1 outfit Lyon did not specify the incident in a statement but said they were responding to a "video circulating on social networks".
The club have moved swiftly and are in the process of identifying the supporter.
Once the fan is identified, they will be barred from home matches at Groupama Stadium and stopped from travelling for games, Lyon confirmed.
L’OL a pris connaissance d’une vidéo qui circule sur les réseaux sociaux. Le supporter en cause est en cours d’identification par les services de l’OL.
— Olympique Lyonnais (@OL) September 19, 2018
Toutes les infos https://t.co/fBmEEV7l3m
Lyon, who have won two of their opening five Ligue 1 fixtures, host Marseille on Sunday.