The former England forward was sent off midway through the second half on Thursday night for punching an opposing player. Video footage also showed Hazell aiming his knee at the player's head.
But Gloucester rugby director Nigel Davies revealed after the game that the Aviva Premiership club will seek sanctions against at least one Mont-de-Marsan player following a game that Gloucester won 11-6.
There are strong suggestions that 34-year-old Hazell might have been gouged during the match.
"Never had a red in 12 years, extremely embarrassed by my actions," Hazell said on Twitter today.
"It was the third time someone tried to severely injury (sic) me, and I reacted."
Hazell can expect a lengthy ban from tournament disciplinary chiefs.
Three other players - Gloucester forward Matt Cox and Mont-de-Marsan pair Scott Murray and Ephraim Taukafa - received yellow cards in the game for unrelated incidents.
Davies, meanwhile, told the Gloucester Citizen that Hazell's eye was "severely sore and very red".
"We'll speak to the citing commissioner, and there will be something done there," Davies said.
"We can't condone what was done from a Gloucester view, but that was a reaction to what went on before.
"We will take our punishment, but I think they (Mont-de-Marsan) need to take their punishment too.
"We'll look at the video, and from what I've seen already I'm sure we will make a complaint.
"The doctor's had a look at Andy's eye. It was severely sore and very red.
"And we took some pictures of that, because that was damning evidence in its own right.
"He's disappointed with himself, but I think there were three incidents before that with the same player and he's caught him off the ball again, and unfortunately Andy snapped."
Gloucester resume their Challenge Cup campaign against another French club - Bordeaux-Begles - at Kingsholm next Thursday night.
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