France want to rediscover 'killer' touch against Wales: Alldritt
The French were outplayed in their opener against Ireland, before edging Scotland and then drawing against Italy.
"The energy was poorly channelled at times, it could have been more effective," Alldritt said of the 13-all draw with Italy which he missed due to an open wound he sustained against the Scots.
"The goal is to return to a more efficient game. We must become 'killers' again... We need it and it will please our fans, too."
Alldritt called on his team to step up to the plate.
"There's not much missing, but sometimes the last step is the hardest to take," said the No 8 who has taken over the national captaincy in the absence of Antoine Dupont, now on French sevens duty ahead of this summer's Paris Olympics.
"It's easy to be champions when everything is going well, when you're on a streak of 10 victories.
"It's in adversity, in difficult moments, that we see true characters, the true strengths of everyone.
"And I am convinced that this French team has a lot of character, that there are many champions in it that everyone will give their best to raise their level."
Coach Fabien Galthie has made eight changes from the team that drew with the Italians, handing debuts to Emmanuel Meafou, Nicolas Depoortere and Leo Barre.
Alldritt said he wanted that trio the "have fun on the pitch... and keep a great memory of it".
"We are in an incredible stadium, certainly one of the most beautiful places to play rugby. There will be adversity, hostility, but when you're a player, that's also what you love."
France's defence coach Shaun Edwards is again back in familiar territory, the former Wigan rugby league legend having served as Warren Gatland's lieutenant during the New Zealander's first spell as Wales coach.
"It's obviously very nice to return and see some old faces I haven't seen for a year or two," said Edwards.
"I had some special times here, won four Six Nations. For me it's one of the best stadiums in the world."
Edwards said Wales, although sporting a record of three losses from their opening three matches, had been "competitive in every single game".
"I thought actually they played very well against Ireland," Edwards said of a game the Welsh lost 31-7.
"We know that they are going to test us for 80 minutes."
Turning to his own coaching role, Edwards added: "From a defensive point of view, we only conceded two tries in the last two matches, conceded 16 and 13 points.
"We're looking to continue to improve because obviously the first game wasn't a good example of the French defence," he said in reference to the 38-17 drubbing Ireland handed France in Marseille.