London Irish hooker David Paice has been suspended for three weeks after being sent off for a headbutt in the 43-41 win over Grenoble on Saturday.
Paice was alleged to have struck Grenoble full-back Julien Caminati with his head; he was dismissed by referee Dudley Phillips after the incident.
The 31-year-old will be free to return to action on 9 February.
Paice, who has the right to appeal, pleaded not guilty at a disciplinary hearing in Dublin.
The offence was deemed to be at the lower end of the scale, while Paice's "good conduct at the hearing" led to the judicial officer reducing the original four-week sanction by one week.
Paice has won eight caps for England but was not named in Stuart Lancaster's training squad for this year's Six Nations Tournament.