World Rugby has responded to French demands for an investigation regarding a photo of referee Jaco Peyper in which he appears to mock the elbow to the head that earned Sebastien Vahaamahina a red card.

Peyper sent Vahaamahina off for his brazen act of thuggery early in the second-half of Sunday's 20-19 World Cup quarter-final defeat by Wales.

In full view of Oita Stadium, the Clermont lock struck Aaron Wainwright on the jaw while France staged an attacking maul, leaving Peyper to make one of the easier decisions of his career.

But the South Africa official has now invited controversy on to himself after a picture emerged on social media showing him posing with Welsh fans and playfully landing an elbow on to 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.

Jaco Peyper pictured with Welsh rugby fans after the RWC quarter-final against France

"World Rugby is aware of a picture on social media of referee Jaco Peyper with a group of Wales fans taken after last night's quarter-final between Wales and France in Oita," a spokesperson said.

"It would be inappropriate to comment further while we are establishing the facts."

Wales head coach Warren Gatland and his France counterpart Jacques Brunel endorsed Peyper's decision to issue the eighth red card of Japan 2019.

The 28-year-old forward, scorer of his side's opening try, spent the rest of the game sat on the bench with his hands on his head.

"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."

Brunel agreed that Vahaamahina deserved to be dismissed.

"The red card I don't contest - when you see the images it's very clear. He did have contact with the face so we can't deny that," Brunel said.

"Of course it changed the game. When you're playing half the match with 14 men it's difficult."

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