Hugo Lloris believes Wales' shock quarter-final win over Belgium offers a timely reminder to France that reputations count for little at Euro 2016.
The hosts conclude the last-eight stage at Stade de France on Sunday against major tournament debutants Iceland, who sensationally dumped England out during the previous round.
Wales, also newcomers to the European Championship, fell behind to a superb Radja Nainggolan strike in Lille on Friday but goals from captain Ashley Williams, Hal Robson-Kanu and Sam Vokes completed a remarkable and deserved 3-1 comeback victory.
"We didn't need to see the Wales result to be wary of every team in the competition," France captain Lloris told a pre-match news conference.
"There have been surprises from the outset of this tournament. It's not enough to just be a top side to make it into the top four.
"The sides who have played the best football are not necessarily in the competition anymore. I think now it is about the team mindset. A team's mental strength can make the different and we must focus on that against Iceland."
A theme of France's campaign has been sluggish starts preceding stirring and successful finishes.
Antoine Griezmann's second-half brace during the last-16 clash with the Republic of Ireland overturned a 1-0 deficit, brought about by Robbie Brady's second-minute penalty.
Asked why his team only seem to perform with their backs to the wall, Tottenham goalkeeper Lloris joked: "That's very French, I would say."
He added: "From my side of things it's not a great problem to not have a great start to the match. What is important is achieving the result you want.
"What does bother me is having [a] spoke between our wheels through a lack of aggressiveness. That's what led to the penalty [against Ireland] and could be a problem for the team.
"Conceding within a couple of minutes could be terminal for the team's chances. So far we are able to bounce back, but it is better to avoid that."
Lloris played alongside Gylfi Sigurdsson for two seasons at Tottenham and is fully aware of the qualities possessed by Iceland's midfield dangerman.
"He's a lovely individual, he's got great values and I really believe he's a great player," Lloris said.
"Unfortunately, the fact that he's Icelandic means he isn't so well known in France, but he is very highly rated on the other side of the channel
"He had a great season with Swansea City, he can score goals with either foot and puts in some great balls from set-pieces.
"Iceland is not a one-man team with Gylfi Sigurdsson, but he is very important to the team."