France lock Bernard Le Roux said team-mate Paul Willemse had difficulty sleeping ahead of Tuesday's disciplinary hearing after he was sent off in the weekend's Six Nations win over Wales.
Willemse, 28, was shown a red on Saturday after appearing to make contact with opposition prop Wyn Jones and will learn the outcome from the Six Nations panel late on Tuesday.
"Paul is stressed. It was an accident. He thought it was the shoulder of the other player, unfortunately his hand was poorly placed," fellow South African-born second-row Le Roux said.
"We'll know more tonight. He told me last night he barely slept. His stomach is in knots. I'm disappointed for him," he added.
Racing 92's Le Roux has missed Les Bleus' two previous matches with a thigh injury but is set to feature in Friday's title decider at home to Scotland.
The hosts will win their first trophy since 2010 by scoring four tries or more in a victory of over 20 points.
Fellow lock Romain Taofifenua is a doubt for the fixture however with a knee problem suffered at the weekend.
"I'm fine, I have no pain. We have an enormous match now," Le Roux said.
Flyhalf Romain Ntamack is expected to start in the French capital with Matthieu Jalibert out after suffering a blow to the head.
Le Roux, 31, is set to face Finn Russell, who also plays for the Parisian club, at the Stade de France.
Influential flyhalf Russell has been sidelined with concussion after scoring 10 points in the loss to Ireland on March 14.
"He's a very difficult player to analyse, even if you play with him," Le Roux said.
"You never know what he's going to do, even if you play in his team. We'll put pressure on him. If he's confident he plays better," he added.
On Sunday, Stade Francais announced France centre Gael Fickou will leave them with two years of his contract remaining for local rivals Racing at the end of the season.
"My reaction is simple. I'm sad to be leaving my Stade Francais team-mates but happy to join those in Racing, who I know very well from playing in France and in Paris," Fickou said.
"Originally it wasn't a decision taken by me. It was a delicate decision to make. It hasn't distracted me at all from my preparation with France."