France's Six Nations game against Scotland is in doubt again on after the French rugby federation (FFR) suspended training on Thursday because of another player testing positive for COVID-19, bringing the total number infected to 11.
The entire squad was now isolating, the FFR said, adding that it was "in close contact with the Six Nations committee."
After two days without a new case in the French squad, Six Nations organizers said on Wednesday the game would go ahead as planned at the Stade de France on Sunday.
But organizers may have to reconsider if they feel the outbreak within the squad is not under control after France's sports minister asked FFR president Bernard Laporte to investigate the series of cases.
France resumed contact training on Wednesday but the FFR had said it would conduct daily COVID-19 testing until Sunday, and one player returned a positive test on Wednesday night.
Several members of staff, including head coach Fabien Galthie, also returned positive tests last week.
"It's always hard to know the origin (of the outbreak)," Laporte told France Info radio on Thursday, before the latest case was announced. "I would like to know. Of course it is something that worries me. I would like if someone is at fault, or not. We are going to investigate this ourselves to see how we got there."