Jonathan Humphreys believes Wales will face "one of the best teams in the world" when they target Guinness Six Nations title and Grand Slam glory on Saturday.
Wales tackle France in Paris, where victory would give them a sixth Six Nations crown and fifth tournament clean sweep.
They head to the French capital having won there on three of their last four visits in the competition, but Wales assistant coach Humphreys is braced for a ferocious challenge.
And he does not subscribe to any theory that France's 23-20 defeat against England, which ended their own Grand Slam hopes, will affect Les Bleus' mindset.
"What you find in all these games is they are won and lost on such fine margins, and that game was like that," Humphreys said.
"I thought England were physical, as we expected them to be, but France are still incredibly dangerous.
"A couple of decisions, and you could argue they would have won that game. Nothing has changed in terms of our perception of France.
"They still have a hell of a lot to play for, and the DNA of the team does not change.
"We believe we are going up against one of the best teams in the world, and that we are going to have to be at our very, very best to get what we want from the weekend.
"There is excitement that we are obviously in the hunt for a big prize, but it is contained by the fact we have got a huge game in front of us and we need to be better than we were in all the games before this."
Wales lost twice to France last year, and Wales forwards specialist Humphreys added: "(They are) the most physical team that we are going to play against, the biggest pack we are going to play against. They are bigger than South Africa.
"Collisions are going to be massive in this game. I keep on saying it, but to get what we want out of this game, we are going to have to be very clinical and at our very, very best.
"There is obviously excitement. Games don't come along like this very often, and we are looking forward to going out there and having a crack at an extremely good team."
Wales have matched their Six-Nations best for one season of 17 tries, while the Triple Crown is already tucked away in the trophy cabinet.
But European rugby's two biggest prizes now stand tantalisingly close, and with a fully fit squad available, everything is geared for the final push.
And Wales will be driven by a core group of experienced players, with captain Alun Wyn Jones at the helm and closing in on a player-record fourth Six Nations Grand Slam.
"There are 25 of this squad who have won big in this tournament," Humphreys said.
"You are led by that, you are led by Al (Alun Wyn Jones), who sets the tone very, very well about this. There is nobody who has been through this more than he has.
"When you have a team meeting and one of those (senior players) stands up and says something, you listen, based on the fact that they have been there, done it and experienced all that stuff. That is worth its weight in gold.
"I think it is belief. It's something you can't coach – belief that you are capable of going out there and doing it.
"When people speak and young people hear, they immediately believe.
"That's massive in sport, especially in these games which are so tight and balanced on a knife-edge. Sometimes, the belief from the core group is the deciding factor."
