France's William Servat has warned his team-mates against overconfidence heading into their clash with Italy.

Marc Lievremont's men are favourites to take the Grand Slam crown after seeing off Scotland, Ireland and Wales in their opening three matches.

Their final clash of the tournament against England has been billed as a mouth-watering tournament decider, with France expected to comfortably see off Italy on Sunday.

However, Servat insists Les Bleus cannot afford to think beyond this weekend's battle with the Azzurri.

"We have progressed in our game," he told the France federation website, www.ffr.fr.

"We know what to do and at what moment because we are beginning to know ourselves in the attitudes and ways of facing different stages of games.

"But at the moment, we are nothing - we have won three matches and then what?

"People are congratulating us but if we fall by the wayside in the match against Italy we will not be anything anymore.

"This match is really more important than it seems."

Italy have long been regarded as the tournament's whipping boys.

However, in the last round of matches they defeated Scotland 16-12 and earlier in the tournament England scraped a narrow win.

Italy's previous away fixture this season ended in a 29-11 loss in Ireland, but Servat believes France cannot afford to underestimate their neighbours.

"They regularly beat Scotland and Wales," he added.

"They will come here to annoy us; they have really progressed.

"They're building themselves little by little in a professional world that doesn't give space to weakness.

"Even though the international results aren't yet at the level, I have seen them progressing for several years now."

France's bid for the Grand Slam crown has been maintained despite a host of injuries which have dogged them since even before the tournament started.

However, they are facing their greatest challenge yet with the news that Mathieu Bastareaud is only fit for a place on the bench.

The powerful Stade Francais centre has been arguably Les Bleus' most impressive performer in the tournament to date but was again forced to train separately today due to a calf injury.

Bastareaud has been replaced in the starting XV by Perpignan's David Marty.

Other changes see Castres' Marc Andreu replace Julien Malzieu of Clermont Auvergne on the right wing, and Biarritz half-back Dimitri Yachvili take the injured Frederic Michalak's place on the bench.

Andreu won his maiden cap as a last-minute replacement for Clement Poitrenaud during the thrilling win over Wales two weeks ago and admits he has never even seen the inside of the Stade de France.

"I've only seen it from the outside," he said.

"I just saw it when passing by a couple of weeks ago on the way to play against Racing-Metro. That's all."