Giuly is one of three players thought to be suffering from swine flu
Two French clubs have hit out at the French Professional League's (LFP) late decision to call off a match after players were diagnosed with swine flu.
The decision to postpone Marseille's match with Paris St Germain's on Sunday left thousands of supporters on the streets and led to clashes with police.
"The decision to postpone the game was taken thoughtlessly and too late," said Marseille chairman Jean-Claude Dassier.
PSG chairman Robin Leproux was also critical of the LFP's decision.
Marseille coach Didier Deschamps added that the postponement of the game "was difficult to understand".
PSG players Ludovic Giuly, Mamadou Sakho and Jeremy Clement were tested for the virus after complaining of fever, coughing and sore throats, according to French media.
The lunchtime decision to postpone the match, due to be played at Stade Velodrome, was taken "on the formal recommendation of the (national) commission of medical experts" the LFP said on its website.
This decision is vindicated by the will to stop all risk of contagion, including among players of the opposing team.
French Professional League
The commission also decided to quarantine all PSG players and staff for 72 hours in bid to contain a swine flu outbreak.
"This decision is vindicated by the will to stop all risk of contagion, including among players of the opposing team, and of complications among the players who are potentially infected," stated the LFP.
The three PSG players involved were not named by the LFP but according to French media, Giuly, Sakho and Clement have been tested in the last 48 hours for the H1N1 virus.
PSG coach Antoine Kombouare had told the club's website on Saturday that he might have to do without the trio for the match.
Several cases of H1N1 flu have been reported among sportsmen in France and two rugby championship games were postponed in August after six players and a coach were diagnosed with the virus.
In the summer, Manchester City defender Micah Richards was found to be suffering from swine flu and in September, the Swedish Football Association recommended players avoid shaking hands after one team was sidelined by the virus.
Police drafted in for the match between arch-rivals PSG and Olympique Marseille clashed with angry Paris fans near Le Vieux Port, the main rail station and a motorway services.
"We are faced with clashes in several areas," said Marseille prosecutor Jacques Dallest. "It could take a few hours before police restore peace and quiet."
But despite the clashes French Football League president Frederic Thiriez insisted he had no regrets over his decision to postpone the fixture.
"If I'd gone against the medical experts, people would have thought I was mad - or, worse in my position - trying to do the dirty on one of the clubs," he told French newspaper L'Equipe.
"To suggest they (scenes of crowd disturbance) are linked to the match being put back is deliberately misleading. Unfortunately, these incidents were planned.
"It's hardly astonishing that matches can be postponed on the morning before an evening."
On Saturday United States president Barack Obama declared swine flu a national emergency. More than 1,000 deaths in the country have been linked to the virus.
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