Charteris could play alongside five France squad members for Racing at Grenoble in the Top 14 on Saturday.
Six days later Wales play France as Warren Gatland's team bid for a potential title decider with England.
"They (Racing players) are all coming back full of confidence and very happy with the new regime," said Charteris.
He helped Wales draw with Ireland and beat Scotland in the opening two rounds while France saw off Italy before beating Ireland by a point.
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Charteris says French players' mindset "is a lot more positive than it had been under the previous coaches".
He added: "It will make them a better team and it certainly won't be easy against them."
The former Newport Gwent Dragons captain says while France's tight play will again be a major obstacle, Wales' pack have improved.
"We know that any French team prides itself on their scrum - that doesn't change," said Charteris.
"We know that we have got to step up or keep things up, but I genuinely feel as a pack of forwards we have raised the bar, not only in the scrum, but defensively at line-out time as well.
"We didn't give Scotland any sort of change or platform to work from, which was hugely pleasing."
In the meantime Wales coach Warren Gatland faces an anxious weekend with the players based outside Wales due to play in domestic matches while his Wales-based players will be rested before the game against France.
Apart from Charteris in France, centre Jonathan Davies could also be in action for Clermont Auvergne.
In the Aviva Premiership, Jamie Roberts (Harlequins), Rhys Priestland and Dominic Day (Bath), Bradley Davies (Wasps), Ross Moriarty (Gloucester) and Tomas Francis (Exeter) could all be in action this weekend.
Wales lock Luke Charteris says the French internationals at his Racing 92 club are full of confidence under new national coach Guy Noves.