Last updated on .From the section Rugby Union

Six Nations organisers are investigating France's use of head injury assessment (HIA) protocols in their defeat by Ireland.

Fly-half Matthieu Jalibert and scrum-half Antoine Dupont were forced off with knee injuries and both players were also registered as requiring HIAs.

Dupont's departure late on allowed starting scrum-half Maxime Machenaud to return to the field, which would not have been permitted without a HIA.

Ireland won the game 15-13.

Six Nations confirmed the HIA Review Processor is looking at the Jalibert and Dupont incidents.

"Depending on their findings, Six Nations Rugby Limited will be considering the next steps in respect of those incidents," it said on Sunday.

Ireland fly-half Johnny Sexton appeared to challenge referee Nigel Owens after Dupont's departure on 75 minutes. France had used all their replacements and would not have been permitted to send Machenaud back on if a HIA was not required.

Owens said the official matchday doctor advised a HIA was needed and stuck with the call, having also sought clarification from the fourth official.

Sexton struck a long-range drop-goal in the 83rd minute to give Joe Schmidt's side a 15-13 victory in their opening game in Paris on Saturday.

"It wasn't our decision," said France coach Jacques Brunel.

"The players did have knee injuries, but the independent doctor decided on the HIA."

France were reprimanded for not following HIA protocols relating to a change of props during the conclusion of their Six Nations victory over Wales in Paris last year.

However, the Untoward Incident Review Group also said there was "no clear evidence" France had tried to obtain a "competitive advantage".