David Wallace and Denis Leamy return for the Heineken Cup clash against the French side and South Africa Wian du Preez will make his debut in this year’s competition at loosehead.

In midfield, Springbok Jean de Villiers makes way for Keith Earls and Lifeimi Mafi to renew their centre combination and McGahan believes the match will not be for fainthearted.

He said: “Once you reach this stage of the competition, round three, four, back-to-back every game and especially so this weekend is dictated by the intensity a side brings to it.

“When you look at the way the breakdown is being refereed, when you look at the carry, look at those places where contact is met.

“That intensity usually wins and usually dictates a lot of the referee's perception of what is happening at the breakdown or on both sides of the ball, so intensity is a very important part of where the game is at the moment.

“They’re a very set-piece dominated side. They play a lot of field position. They kick a lot from their back forty, back fifty so they don't play a lot of rugby from there at all.

“But their major threat is working their way from kicking, from forcing penalties at the set piece, to get down to the bottom twenty and they look to grind you down from there.

“Without a doubt the forwards will be the battle piece this weekend.”