Sydney - The Wallabies' three most exciting backline stars engaged in a drunken brawl in Paris last November, it was alleged on Monday, threatening to disrupt Australia's Rugby World Cup campaign.Television reports said that James O'Connor and Wallabies playmaker Quade Cooper had a late-night scuffle with team-mate Kurtley Beale in the lead-up to the season-ending Test against France.The reported fight did not appear to affect the Wallabies just days later at Stade Francais when they thrashed the French 59-16 in their biggest win of the year.The three star backs are normally inseparable in the Wallabies camp but the timing of the allegations could not be worse for Robbie Deans's highly-rated team, reports said.Australia have the chance this Saturday to end a 10-year Tri-Nations drought with a series decider against the All Blacks, while the World Cup kicks off in New Zealand early next month.The Australian Rugby Union (ARU) said it has begun investigating the matter following newspaper reports of an alcohol-fuelled Paris incident.An ARU spokesperson said all relevant parties had been questioned, but inquiries would continue on Tuesday when Deans will name his 22-man team for the Tri-Nations match."We will not be discussing players by name," an ARU spokesperson told Australian Associated Press on Monday."Allegations of an incident in Paris last year were brought to our attention by the media. There have been no complaints made and we have not ascertained there was police involvement."These allegations, which appear to be widespread throughout the media community, have come to us and we have made inquiries into these allegations and we continue to make inquiries."Television news also alleged Cooper and other players were on drinking bans following misbehaviour at the start of the late-season tour in Hong Kong last year.O'Connor, 21, was on Monday fined A$10 000 and given a one-match ban by the ARU, ruling him out of the Tri-Nations decider, for missing last Thursday's World Cup squad announcement and team photo following a reported bout of drinking in Sydney.