Forwards coach William Servat emerged as the third case, despite having tested negative 24 hours earlier.
Head coach Fabien Galthie was confirmed to have coronavirus on Tuesday and must isolate for a week. The other positive case has not been identified.
But all of the playing staff tested negative for a second time in additional tests on Tuesday evening.
The French Rugby Federation said the positive test for Servat “brings to three the number of positive Covid-19 cases in the camp. Up to now no symptoms have been detected”.
“Additional PCR tests conducted on Tuesday evening indicated that every player was negative, confirming the results from tests taken on Monday.”
The players will undergo another test on Wednesday morning before returning home for a few days off.
They will return to their Marcoussis training base on Sunday to prepare for their next Six Nations match against Scotland in Paris on February 28.
The virus all-clear for the players comes as a welcome boost for the side that now top the Six Nations table after beating Italy and Ireland.
The holding of the Six Nations had been in doubt before it started in early February after the French government called for further guarantees about the competition’s safety protocol.