Former Arsenal captain Patrick Vieira has backed France to beat England in their Group D opener in Donetsk on 11 June.
Both sides have injury concerns ahead of Monday's clash, with England defender John Terry nursing a tight hamstring and France's Yann M'Vila doubtful with a damaged ankle.
But Vieira insists Laurent Blanc's side have put the ignominy of the 2012 World Cup in South Africa behind them and believes the winner of Monday's match will top Group D.
"Neither country had an enjoyable World Cup in South Africa, but the problems which undermined France are all sorted now," Vieira told the Daily Mail.
"The French federation dealt with it decisively and now there is a new coach, a new philosophy, a new approach to the game - and Laurent Blanc is seeing the benefits of winning games, which breeds confidence and unity."
France are unbeaten in 21 games and scored nine goals in their three pre-tournament friendlies - including a 4-0 victory over Estonia on Tuesday.
"You have to be aware of the array of talent going forward," said England manager Roy Hodgson, ahead of Monday's clash.
"They're great in the final third. The main thing is to nullify the threat they create around our penalty area."
Nevertheless, Vieira believes France have problems in defence, after losing Bacary Sagna and Eric Abidal.
"France have problems at the back, while England will be without Rooney - so who is going to score the goals, who is going to supply that bit of magic for them?" said Vieira. "For both managers, there may be more questions than answers.
"For me Joe Hart is one of the best goalkeepers in the world and France will have high hopes of Karim Benzema, who has reached the top level with Real Madrid this season, so both teams have real talent.
"They are two teams who will fear each other. The team who lose that game will be in big trouble."
With the runner-up in Group D expected to face Spain in a quarter-final on 23 June, Vieira's former manager Arsene Wenger remains adamant England's European Championship campaign will be as good as over if they lost to France.
'The opening game is England v France and there is no Rooney. You would say that is a game that you cannot afford to lose," Wenger told Arsenal's official Web site.
"Why? Not because you cannot catch up, but (because) the pressure inside the country becomes tremendous straight away.
"That game could dictate the whole group. If it's a 0-0 draw, the group is all open, but if someone loses they have a very good chance of going out because Ukraine will beat one of the two, you would say, and Sweden are a hard team to beat."