France have called for World Rugby to investigate a photo of referee Jaco Peyper in which he appears to mock the elbow to Aaron Wainwright's head that earned Sebastien Vahaamahina a red card.
Peyper sent Vahaamahina off after he struck Wainwright on the jaw while France staged an attacking maul.
The South Africa official has now invited controversy after a picture emerged on social media showing him posing with Welsh fans and playfully landing an elbow on the head of one.
"This photo if it is true is shocking and explanations will be necessary," French Rugby Federation vice president Dr Serge Simon said on Twitter.
Wales head coach Warren Gatland agreed with the referee's decision to give the french player a red card.
"The officials dealt with it appropriately. I don't think anyone could complain about that. The right decision was made," Gatland said.
"Rugby is heat of the moment stuff and he made an error of judgement. When you have got a lot of testosterone involved in some pretty high intensity games, that will sometimes happen. He's made a poor decision."
World Rugby announced that Vahaamahina will face a disciplinary hearing on Thursday following his dismissal.
He will appear before an independent judicial committee chaired by England's Mike Hamlin.
Wales will face South Africa in the semi-finals on Sunday.