Nicolas Mas stormed out of a press conference on Tuesday as French unrest boiled over ahead of Saturday's RBS 6 Nations title decider with Ireland in Paris.
The France prop reacted angrily to criticism of France's scrum and tight play in the wake of last weekend's lacklustre 19-17 victory over Scotland.
France, Ireland and England can all still claim the Six Nations title this weekend.
Philippe Saint-Andre's Les Bleus host Ireland in the tournament's final game on Saturday night, with Brian O'Driscoll making his 141st and final Test appearance.
Ireland have won just twice in 42 years in Paris, but it is the weight of expectation, not history, burdening the French.
Montpellier front-rower Mas snapped when the assembled media suggested France have been too slow to react to scrum law changes.
When asked why the French have not enjoyed the scrum dominance of the past, Mas said: "I don't know why, you tell me.
"I have been doing the same things for 10 or 15 years, you want me to change overnight?
"It [the scrum] is like a child who has lost its bearings, how far will it go?
"It's a real shame."
Rumours of French rifts have circulated ever since their comprehensive 27-6 defeat to Wales in Cardiff on February 21.
After a slender 26-24 home victory over England and routine 30-10 triumph over Italy, the French surrendered any Grand Slam hopes to Warren Gatland's men.
Their edgy win in Scotland did little to ease the in-fighting, as evidenced by Mas' erratic press conference behaviour.
Saint-Andre's pragmatic styles of play have left a host of former France coaches and stars underwhelmed, with Bernard Laporte and Marc Lievremont the latest quizzical commentators.
Refusing to countenance the interrogation, Mas cut Tuesday's press conference short.
"We don't judge the scrums on penalties, what strange logic," said the 33-year-old, under fire for France's indiscipline at the set-piece.
Jean-Marc Doussain's 78th-minute penalty stole France the victory over Scotland at Murrayfield on Saturday.
Mas stoutly defended France's decision to play for the pivotal penalty in Scotland's 22 but was forced to concede it was an "embarrassing" route to victory.
"If we can win all our matches with penalties like that, we will take anything: the main thing is to win in the end," said Mas.
"Perhaps that does not please people, but we were sure of our approach, and it was embarrassing not to score [a try] from it."
As tensions rose, one journalist jokingly remarked that the French were not playing poorly on purpose.
"This is not funny," retorted Mas, before storming off, bringing a premature end to the interview.