Perpignan president François Rivière has written a letter of complaint to the ERC following his side's heavy Heineken Cup defeat to Munster last weekend.
USAP were thrashed 36-8 at Thomond Park on Sunday but Rivière was left fuming by the performance of English referee Greg Garner.
Rivière told local newspaper L'Indépendant that he had sent "firm letter of complaint" to the tournament organisers.
"I cannot remain inactive in the face of such injustice," said the club president.
"Between the Guitoune try which is denied us, the penalty try and 14 to 4 the penalty count against us, it is my duty to do something. It is not acceptable to let this go. "
Meanwhile, Perpignan have suffered a further setback with the news that French international fly-half Camille Lopez has been ruled out for six to eight weeks with an ankle ligament injury.
Lopez suffered the injury during the defeat in Limerick and was replaced by young Italian international Tony Allan.
Lopez will now miss the return clash against Munster in France this weekend as well as three Top 14 matches. He is in a race against time to be fit for the final European pool clashes against Edinburgh and Gloucester.
With Welsh playmaker James Hook given time off this week, Allan is set to start against Munster on Saturday.