France's ability to confound by switching attitudes is well known in sporting World Cups. At this event they lost to Tonga on October 1 and eliminated England a week later.
It is ironic, then, that France look at their opposition in the semi-finals of the Rugby World Cup on Saturday and wonder, "Who are these guys in Wales shirts?"
The French are used to facing Wales teams that have tended to be sloppy, tactically woeful, mentally fragile and unfit.
James Hook, who will start at fly-half for Wales in place of the injured Rhys Priestland, was on the bench for the quarter-final against Ireland but was impressed enough to describe their 22-10 win last weekend as a "pretty complete performance". He was sure that if the Welsh team can keep surfing the crest of their wave that they can beat the French for only the second time in their last eight match-ups.
"We have probably surprised ourselves a little bit at how we've performed here, but surprised other people a lot more," Hook said.
Only eight months ago, Wales were on an eight-match winless streak, their worst run in eight years. But two summer camps in the Polish Olympic training village of Spala have risen to mythical status in the way the team bonded with dawn-to-dusk fitness work.
"We are obviously getting accolades for the way we have been playing, but once you get to knockout games you realise that these are the pressure games and when you want to be at your best," Shaun Edwards, the defence coach, said. "We feel the more pressure that is on us, the better we play."
About 50,000 have snapped up free tickets for the Millennium Stadium in Cardiff to watch the match live on the big screens at sunrise.
The forwards coach, Robyn McBryde, said Wales are aware of the attention and embrace it. The relative youth of the squad meant they were "enjoying the moment".
Marc Lievremont, the France coach, has done his best to up the pressure by praising Wales for their intelligence, team spirit and quality of rugby. Lionel Nallet, the France lock, said that Wales are a different team, and he did not mean the faces.
But France also have been different, this week. The French spent the first month of the tournament riven by open dissent, largely caused by Lievremont's public criticism of players and the French media, and his renowned erratic selections. Yet the team overcame two pool losses to slip into the quarter-finals, where they outclassed England and justified the coach's unconventional methods.
For today's match, he wants his players to motivate themselves by visualising the desolation they would feel at the final whistle if they lose at Eden Park.
"Perhaps an anger against ourselves, by telling ourselves we have no right to slip up in terms of commitment and concentration, which is so indispensable in a semi-final," he said. "We need to feel confident to get good results. The first half we played against England and the good week we've had in training correspond to that."
Grinding out results is not the France way; going from the sublime to the ridiculous, and then back again, is.
"The Anglo-Saxons, the Welsh, have shown this consistency in their matches," he said. "We Latins, French, need something else. A form of anger, affection. We've spoken it among ourselves, we'll need a mixture of that."
Lievremont was open about the pressure he feels. "I'm probably more stressed than I was last week," he said. "Above all, I'm scared of the Welsh."