Stade Francais ended English involvement in the Amlin Challenge Cup with an impressive 36-20 victory at Bath, but the win was soured after scrum-half Jerome Fillol allegedly spat at opposite number Peter Stringer.
The two had already exchanged words once, but then clashed again before a 25th-minute scrum. Nothing untoward was seen by referee Nigel Owens and his assistants at the time, but replays of the incident have emerged showing Fillol spitting straight in Stringer's face.
Speaking after the game, 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. That's as low as you can probably go. When you are on the end of something like that you are rattled by it, but try not to dwell on it. It's out of my hands now."
Waisea Vuidravuwalu scored two of Stade's four tries, and helped lay on the other two for full-back Hugo Bonneval, with fly-half Jules Plisson, Fillol and replacement Jerome Porical all contributing points through the boot.
Bath secured a penalty try and consolation scores from replacements Michael Claassens and Jack Cuthbert, while Stephen Donald kicked five points, but it was nowhere near being enough as the home side were outclassed.
Bath first-team coach Toby Booth said he had not seen the spitting incident, but added: "Peter is pretty angry, I have not had time to speak with him but I would be pretty disappointed - as I am sure everyone would be - if that is proved to be true.
"There is no place for that at all."
Fillol is almost certain to be cited, given the damning nature of the video footage, and could face a lengthy ban.
Booth admitted his side had been second best by some distance.
"It was very disappointing, it was a big game and a big occasion for us and it did not go as we would have liked," he said. "From a physicality point of view we were found wanting, and at the breakdown as they scored three tries off turnovers."