France centre Sofiane Guitoune has said the most important aspect of their preparation for Sunday's World Cup quarterfinal against Wales has been learning how to stop themselves "acting like idiots" when they are in positions of dominance.

In their pool matches against Argentina and Tonga, the French started well but ended up hanging on desperately and even against the United States they needed a late surge after a 12-0 lead was trimmed to 12-9 with 15 minutes to go.

Nobody in the camp needs any reminding about what happened last time they faced Wales, in the opening game of this year's Six Nations. They played superbly in difficult conditions to lead 16-0 at halftime in Paris, only for the Welsh to storm back and claim the 24-19 win that set them on the way to a Grand Slam.

That made it seven wins out of eight in the fixture for Wales since France edged the 2011 World Cup semifinal by a point and there is a collective will in the French squad to stiffen their resolve for Sunday.

"In those pool matches, we took a quick lead and then the outcome always ends up the same," Guitoune told a news conference on Tuesday.

"Perhaps because everything is going too well. I think it's more in our heads than it is a structural problem.

"We've talked about it, reset our strategies so that when we start to act like idiots, to not respect the game plan, to panic for no reason, we can start off again on the front foot and not make ourselves afraid until the end of the match."

France look better equipped now to deal with the Welsh attack, with new systems put in place by assistant coach Fabien Galthie.

France centre Sofiane Guitoune has said his side has a chance to make the semifinals if they don't act like idiots. Photo by FRANCK FIFE/AFP via Getty Images

"We are better set up to counter-attack and put Wales in difficulty and we've really worked on that, said fellow-centre Gael Fickou.

"Our speed will be the key to the match. The moments when we've been unsure, when we've slowed the game down, have been when we didn't win our individual duels."

Fickou said he had also been thinking about the one game they have won against Wales in the last eight years -- the remarkable 2017 match where they eventually, and controversially, triumphed 20-18 when Camille Lopez converted Damien Chouly's try in the 21st minute of stoppage time.

"It had been a long time since I'd felt emotion like that. That's what you play for," he added. "It was a fantastic feeling, with Chouly's try which saved us all. It's one of those great memories."

France's chances of a repeat on Sunday are likely to be considerably hampered if scrum-half Antoine Dupont and winger Damian Penaud fail to make the team as both battle back from injuries.

Dupont has a back problem but Guitoune said he was "running like a rabbit" in training and was confident he would make Sunday's match.

Penaud has an abdominal strain but is also expected to start.