Former Wasps and Biarritz back-row Serge Betsen insists France can mount a serious challenge for Six Nations glory.

France will go into the tournament as joint-favourites after a four-Test unbeaten run.

Having beaten Argentina in the summer, they went on to thrash the Wallabies before seeing off the Pumas for a second time and then toppling Samoa.

Those performances, though, came on the back of a disappointing Six Nations campaign last year - with Les Bleus finishing fourth.

However Betsen, who is now on the coaching staff at London Scottish, believes that the side never recovered from having to play three games on the bounce after their initial clash with Ireland was called off just before kick-off due to a frozen pitch.

"I think France will do very well," Betsen told Sky Sports.

"It was difficult for them last year because of the postponed game with Ireland in Paris. It was then very hard for them challenge because they had three hard games in a row while others got to rest.

"I think it is going to be a lot better this time as they have been going really well. In the summer they mixed up the young players and the November Tests confirmed that this group can compete."

Fantastic

Yet despite their current form, the 38-year-old, who won 63 caps during a distinguished career, believes France won't have things all their own way.

"The side did really good in the autumn with three fantastic games and to be top five in the world," Betsen said.

"I am not sure they can win the grand slam, though, as they have three games away while they will be contesting with England and Wales."

Having spent three seasons playing for Wasps - even captaining the Adams Park side - Betsen has an inside track on two of England's rising stars, Joe Launchbury and Billy Vunipola.

"I am really pleased for Billy," he said. "I played with him during in my last contract at Wasps, along with Joe Launchbury.

"Billy is really powerful and very skillful. I hope he will be a success. He has deserved his chance with the way he has played for Wasps."

Serge Betsen will be playing for a France Legends XV against a British and Irish Lions Legends XV at the Stoop on February 22 to help raise money for the Wooden Spoon charity and the Serge Betsen Academy, which helps underprivileged children in Cameroon. For more information visit www.sergebetsenacademy.com/index-en.htm