Bath scrum-half Peter Stringer was furious after he was spat on by Stade Francais' Jerome Fillol during the English side's 36-20 defeat in the Amlin Challenge Cup quarter final.
The two scrum-halves clashed before a scrum in the 25th minute. Nothing untoward was seen by referee Nigel Owens and his assistants at the time, but replays showed Fillol spitting straight in Stringer's face.
Fillol is almost certain to be cited, given the damning nature of the video footage, and could face a lengthy ban.
Former Ireland scrum-half Stringer said: "Obviously it is a bit raw at the moment, but it happened on the pitch and there is no place in the game for it.
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