The build-up to tonight’s crucial meeting between Ireland and France in Paris turned sour yesterday with Brian O’Driscoll and Eddie O’Sullivan accusing the French media of an orchestrated attempt to unsettle the side before the pool D encounter, which will make or break not only each country’s hopes of reaching the World Cup quarter-finals but also individual careers and reputations. The stakes are that high.

Ireland are incensed by reports about Ronan O’Gara, the fly half, and wasted little time in venting their anger. “We’re a very tight-knit group. We’ve all been together for the best part of three or four years,” O’Driscoll, the captain, said. “We’ve developed very strong friendships and when you see a slur on someone’s personality and private life, you take it personally yourself. You wouldn’t wish that on anyone, least of all someone on your own team. So we’ll put it in the pot. We don’t forget easily. It’ll be used as extra motivation.

“If you’re a cynic, you could say the story was an attempt to knock things up in the days building up to the game, to throw a few sparks around the camp and unsettle us a little bit. But we’re a bigger team than that. We’re not going to let something so stupid and so unfounded shake us. It will galvanise us more than anything.”

O’Sullivan, the coach, said that O’Gara would not be distracted. “He was a bit upset with what happened. It was an attack on him on a personal level, which was totally unfounded as well. It was just really nasty stuff. But he’s a tough individual. It’s not going to put him off. If anything, it will make him more determined.”

The pressure is such that past form – France have won five matches in succession against the Irish, including a last-gasp win at Croke Park in the RBS Six Nations Championship in February - will count for nothing. France cannot afford to become the first host nation to fail to reach the knockout stages, while Ireland’s hopes will be virtually dead if they lose. For a side touted as dark horses for the World Cup, an early exit would be embarrassing and lead to an inquest.

France have made four changes, but the biggest surprise is the switch they do not make, with David Marty again preferred to Yannick Jauzion at centre, while the popular Sébastien Chabal keeps his place in the second row. Ireland have pinned their faith in Eoin Reddan’s ability to vary the game from scrum half, at the expense of Peter Stringer, and their collective desire to eliminate many of the 71 errors and turnovers committed against Namibia and Georgia.

France eased into their stride against Namibia, but they have been chopping and changing selectorially; fly half remains a problem and the back row is an untested unit. Given the success of Argentina’s game plan a fortnight ago, do not be surprised to see Clément Poitrenaud exposed to some early high balls. It could just be the occasion for a return to the boot and bite of yesteryear.

If Ireland can stop France establishing an early advantage, there will be all to play for, and do not be surprised if O’Sullivan’s side edge what will be the most gripping encounter of the tournament to date.

How they line up

France: C Poitrenaud; V Clerc, D Marty, D Traille, C Heymans; F Michalak, J-B Elissalde; O Milloud, R Ibañez, P de Villiers, S Chabal, J Thion, S Betsen, T Dusautoir, J Bonnaire.

Replacements: D Szarzewski, J-B Poux, L Nallet, Y Nyanga, L Beauxis, Y Jauzion, A Rougerie.

Ireland: G Dempsey; S Horgan, B O’Driscoll (right), G D’Arcy, A Trimble; R O’Gara, E Reddan; M Horan, J Flannery, J Hayes, D O’Callaghan, P O’Connell, S Easterby, D Wallace, D Leamy.

Replacements: F Sheahan, S Best, M O’Kelly, N Best, I Boss, P Wallace, G Duffy.