Former France international Sébastien Chabal faces a hefty ban for throwing a punch during Lyon's second division fixture against Agen last weekend.
The back-row was on Thursday summoned to appear before the French national league of rugby's disciplinary commission on January 3.
If guilty Chabal could be suspended for between two weeks and one year over the incident which has become a much-viewed YouTube hit.
Chabal found himself in hot water after striking Agen's Marc Giraud who was holding onto his shirt in the Pro D2 fixture last Saturday. The force of the blow knocked Giraud unconscious.
He was shown yellow for the strike which he later described as "regrettable but a reflex action".
The 36-year-old, an iconic rugby figure, earned 62 international caps between 2000 and 2011.