And if that wasn't tough enough, lying in wait on the bench is perpetual breaker of Irish hearts Vincent Clerc, scorer of a last-minute try in the first rugby union game at Croke Park.
But McFadden, who is more at home in the centre, has already produced some impressive performances in the back three against French sides in the Heineken Cup this season and is backing himself to do so again.
"I had four matches in the Heineken Cup against Clermont and Racing and I felt I did well in all four games," said McFadden.
"They've some seriously exciting players and you have to go into those games really on your toes. But I think it brings the best out of me.
"It's really exciting for me to be marking Maxime. I've watched him a lot with Toulouse.
"He's very quick and he can play full-back as well. There's a few people not making it, Vincent Clerc and the like, so they're not struggling for talent in that area of the pitch.
"They've got these open-field runners who can score tries from nothing against the best teams.
"So we can't afford to turn over the ball like we did against Italy or we're going to be punished badly."