RTÉ rugby analyst Donal Lenihan believes that France's 7:1 split and how successful they are in targetting Sam Prendergast could decide the day when Ireland host Les Blues at the Aviva Stadium this weekend.
Simon Easterby's side welcome France to Dublin for a game on which Ireland's Grand Slam hopes hinge, while a win for the visitors would most likely set them up to win the Six Nations.
French boss Fabien Galthie has rolled the dice and opted for a 7:1 split on the bench, just as they did in victory over Italy last time out.
Galthie has named just one back on his bench, with scrum-half Maxime Lucu, looking decidedly out of place alongside the giants of their forward pack.
Speaking on Morning Ireland, Lenihan explained how he believes that Galthie is taking a massive gamble with his bench selection, albeit one that could pay off handsomely.
He said: "You can replace practically your entire forward unit 10 minutes into the second half and that means you can now pick players who are 22 or 23 stone who don't have the aerobic capacity to play for 80 minutes.
"They know in advance of the game that they'll be taken off five or 10 minutes into the second half. So the power that you're bringing on is absolutely huge. It's frightening.
"France did it for the first time against Italy and I've no doubt in my mind they did that with the Ireland game in mind. The fact that they were able to bring on so much power meant they ended up scoring 11 tries.
"They've got a massive points difference over Ireland going into this game, which means that if they manage to beat Ireland, to be very difficult for us to surpass that points difference and win the championship.
"But there's inherent danger with the 7-1. You go back to the Ireland game against Scotland in Murrayfield where Scotland lost two backs and Finn Russell and Darcy Graham in one incident alone.
"If France get one injury, their one back on the bench is Maxime Lucu, who's a scrum half. So then you're having to move Antoine Dupont, who's the best scrum half in the world, and you're taking him out of position. So there are risks involved in it."
Lenihan believes that the other key factor at the Aviva Stadium, will be how rookie out-half Prendergast copes with the pressure.
Prendergast will come if for his seventh senior appearance against France and given what's gone on in the championship so far, France look set to target him defensively.
"There's a lot of focus on Sam," said Lenihan. "He only has six caps under his belt. Ronan O’Gara often said that your first 10 caps as an out half, where you're controlling the game, is almost a haze.
"Defensively [Prendergast] came under pressure against Wales, but people don't remember that for 20 minutes of that game, Ireland had only six backs against seven Welsh, so there was huge space to cover.
"I've no doubt that France will target Prendergast defensively.
"He's an amazing player. His decision making under pressure, his ability to make the right pass at the right time for such a young player is astonishing, but it's his kicking game days that will be under focus.
"Ireland are kicking a lot more than they used to and the aerial battle is going to be huge.
"Bookies have France as favourites and I can see why. But there is home advantage and we've beaten France in the last two years.
"It will be a massively emotional day with the three lads, Cian Healy, Conor Murray and Peter O'Mahony finishing up. I'm hoping that Aviva may just get Ireland over the line, but it's going to be very difficult."
Watch Ireland v France in the Six Nations on Saturday from 1.15pm on RTÉ2 and RTÉ Player. Follow a live blog on rte.ie/sport and the RTÉ News app. Listen to live commentary with Saturday Sport on RTÉ Radio 1.
Watch Ireland v France in the Under-20 Six Nations on Friday from 7.35pm on RTÉ2 and RTÉ Player.
