France centre Benoit Baby admits he is concerned about what punishment may be meted out to him at Wednesday's disciplinary committee hearing in London.
Baby is facing the three-man committee after being cited for an incident during his side's 26-19 RBS 6 Nations victory over Ireland on Saturday.
Baby, who was making his international debut for France, is alleged to have headbutted Ireland captain Brian O'Driscoll in the 47th minute of the clash at Lansdowne Road and was cited under the International Rugby Board law 10.4 (a).
If found guilty, he could miss Les Bleus' final RBS 6 Nations match against Italy on Saturday.
"I am quite worried about the penalty," said Baby, who will travel to London with team manager Jo Maso, coach Bernard Laporte and the French rugby federation's lawyer.
"I am going to talk to the federation's lawyer about my defence but I don't really have a precise strategy.
"I really regret what I have done. I have never been booked in my career. I apologised to Brian after the match.
"There are more cameras on the pitch for the Six Nations, that's why it is so important to be careful about what we do."
Baby has been provisionally selected to start for France in the meeting with Italy in Rome's Stadio Flaminio and remains hopeful he will make the clash.
"I am in the starting XV and very proud of it," added Baby.
"I really hope I will make the trip to Rome this weekend. I would have liked to stay in Marcoussis on Wednesday to train because the better you train the more chances you have to beat your rivals."
France team manager Jo Maso gave his full backing to Baby and it the incident down to inexperience.
"This is a real shame because it was Benoit's first international match and it was a success," said Maso.
"We saw him do that gesture and this is something that we should never see in rugby, but on a sporting level I will defend him, this is a young person's mistake.
"We will plead for leniency, he is only 21. He was himself surprised at his own action."
O'Driscoll was not injured and even offered to exchange shirts with Baby after the match - a gesture which Maso applauded.
"O'Driscoll made sure his shirt would go to Baby after the match, this was a class reaction," added Maso. "Benoit was very surprised too."
The RBS 6 Nations Championship 2015 was not poised to go down as one of the more "vintage" Championships, though there was great anticipation as the action headed into its final day. What transpired was something that nobody could foresee: "The Greatest Day in Rugby's Greatest Championship."