Serge Betsen feels the "unbelievable" Shaun Edwards has already made a big impact since he was appointed France defence coach and declared "this is just the beginning".
Edwards was lured across the English Channel to join a new-look Les Bleus coaching set-up under Fabien Galthie after 12 years as Wales defensive guru.
It was clear that the hugely respected, no-nonsense 53-year-old has already stamped his authority early in his new role with the manner in which France defended for their lives in a victory over England in their Six Nations opener.
Edwards returns to Cardiff on Saturday for France's showdown with his former employers at the Principality Stadium on what promises to be a pivotal weekend in the battle for the title.
Betsen has first-hand experience of Edwards' coaching skills from his time at Wasps and the former France flanker has paid tribute to the Englishman.
He told Omnisport: "Shaun Edwards used to be my coach at Wasps. He coached me for three years, he's an unbelievable coach, very passionate and very effective with what he does.
"He's one of the best defensive coaches in the world and everybody who he coaches, you can see the impact he has made. I'm looking forward to seeing how he is going to empower the French players for this game because it's really fine margins and those margins are so important.
"I don't feel he'll be looking to use his past experience with Wales as an advantage so much, but what he is really good at [is] empowering people and he'll make sure the players know how to be the best they can be."
Betsen revealed Edwards asked to pick his brains before embarking on his new challenge.
"I really appreciated the fact that Shaun asked to meet with me before he went to France, to try to understand the French mentality, et cetera," he added.
"As a Frenchman and someone who understands his coaching philosophy, I think he made a very good decision to try to understand the people he would be working with and the culture, to ensure he can adapt himself and make a difference.
"We saw the impact he has made in the game against England, not so much against Italy. He brings to the team with instilling discipline, effectiveness, attention to detail and this is just the beginning.
"What people remember from Shaun Edwards is the blitz defence and I want to see the French team being able to apply that at some point."