France head coach Guy Novès insisted that Uini Atonio's substitution was due to an injury concern after his side's win over Wales.
Atonio was withdrawn for an HIA check after complaining about a back injury, and replaced by Rabah Slimani for the final stages of an incredible 20-minute period of overtime at the end of the match in Paris.
France went on to win with a try in the 100th minute from Damien Chouly, leading to accusations from Wales boss Rob Howley that the game had been brought into disrepute.
"They told me he [Atonio] was injured, so I have to take my responsibility," Novès told the Press Association.
"We will do a medical check-up. I hope the injury is not too serious, and he will be able to play again soon."
Away from the controversy, Novès was full of praise for France after they kept battling for a third win of the Championship, which leaves them finishing in third place behind Ireland and champions England.
"I am very proud of the players, and I think the public loved it. The French team has shown what it can do this season," Novès said.
"Many matches can be a benchmark. It is too early to say what was good and bad for us in the tournament.
"We have to remain clear-headed. The players have learnt that if you keep the ball, you will score the try."