This means the 27-year-old will miss the remainder of the season, and his suspension will carry on into next season.
He was found guilty of a grade E offence, and given a £300 fine in addition to his suspension.
Team mate Oliver Wilkes was also suspended by the RFL, for a late challenge on Marginet during the same game in Perpignan. Wilkes was given a one match ban and a £300 fine.
Roby was cleared to play after being charged with a dangerous throw in his side’s win over Castleford at the weekend.
However Castleford, who play Leeds in the other semi final on Sunday, will miss John Davies after he was found guilty of dangerous contact on Roby in the same match.
Warrington’s Mickey Higham will miss all of his side’s matches throughout August after being found guilty of a chicken wing tackle against Bradford.
Higham was given a two game ban, which means he will not play in his side’s next home game against Wakefield, or travel to Catalan a week before the Challenge Cup final.
Liam Higgins was also handed a one match ban for a high tackle on Crusaders’ Jordon James in Wakefield’s 40-6 defeat at the Hearwell Stadium.