The uncapped Gael Fickou will replace Fritz on the bench. The 18-year-old trained with Philippe Saint-Andre's men ahead of the championship but has since been playing for the Under-20s.
A French team spokesman said: "Florian Fritz will not be fit for Saturday. He has a blister that has infected his left foot. He has been replaced by Gael Fickou."
Meanwhile, head coach Saint-Andre insists he is firmly focused on ending a poor campaign on a high.
Only victory over Scotland will give them a chance of avoiding the wooden spoon for the first time since 1999, and Saint-Andre wants his team to put on a performance in front of their home fans.
"I have told the players they must battle for 80 minutes and take the game by the scruff of the neck," he said.
"I want them to deliver pleasure to the public, to the Stade de France and to French rugby. I want them to finish on a high note in what has been for us a very, very bad Six Nations."