The French stumbled through the group stages and were in an apparent state of disarray after losing to Tonga but found their stride last weekend to send England home.
France shocked the All Blacks at both the 1999 and 2007 World Cups but lost the following week - and Marc Lievremont's men are bidding to avoid a third consecutive semi-final defeat.
"I've heard their coach say they have to overcome the obstacle of only having one big performance in them," said Wales defence coach Edwards.
"But if you look at France in the Six Nations over the last five or six years I think they have won it the most, which shows they have consistently performed over five games.
"It is in the France team to be consistent and they do have the ability to be consistent.
"There has been one standout performance - everyone talks about their victories over the All Blacks - can they back it up the week after? We'll find out on Saturday."
Wales have lost to France on six of their last seven meetings but Edwards believes Saturday's Eden Park showdown will be a "50-50" encounter.
"What has been part of our problem against France in the past is that we have harmed ourselves," Edwards said.
"I remember in 2010 we gave two interceptions to them. In Paris we had a charge down that was pivotal in the game.
"We have to make sure that if France do get points against us they have to earn them.
"What we have tried to do throughout the competition is improve on every game.
"This will be no different. We will have to be even more accurate this weekend because it is the semi-final."
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