An apparently furious Marine Le Pen on Wednesday accused her 86-year-old father of taking the party hostage in an attempt to damage her and said she intended to stop him standing as an FN candidate in regional elections at the end of the year.
Jean-Marie had been expected to head the party's slate in the Provence-Alpes-Côte d'Azur region around Marseille, which the FN hopes to win control of.
And Marine said she would organise a meeting of the party's top executive committee, on which both father and daughter sit, to take disciplinary action against him.
The spark for this fury was an interview in the fringe far-right paper Rivarol in which Jean-Marie attacks Prime Minister Manuel Valls as an "immigrant".
"Valls has been French for 30 years, I've been french for 1,000 years?" he says. What is Valls's real attachment to France? This immigrant, has he completely changed?"
Le Pen Senior also says that he has never considered Marshal Philippe Pétain, the head of the government that collaborated with the Nazis in World War II, a traitor.
"They were very harsh with him at the liberation," he comments. "And I never considered that people who continued to respect the marshal as bad French people whom I wouldn't associate with."
In an earlier radio interview he pointed out that there were "fervent Pétainists" in his party's ranks.
The Rivarol interview follows last week's repetition of his assertion that the gas chambers in which the Nazis murdered Jews, Roma and gays, were a detail in the war's history.
Marine has condemned these statements, which she clearly sees an attempt to sabotage her efforts to clean up the party's image, in particular by distancing it from anti-Semitism.
FN deputy leader Florian Philippot declared Wednesday that there was now a "definitive split" with the party's founder.
Marine Le Pen's partner, Louis Aliot, another vice-president, tweeted that "our political disagreements are now irreconcilable".
And Marion Maréchal Le Pen, Jean-Marie's granddaughter and one of the movement's two MPs, earlier described his gas chamber comment as a "pointless provocation".
What action could be taken, apart from the ban on standing in the regional elections, was unclear on Wednesday, however.
Jean-Marie is honorary president but the party statutes provide no means of stripping him of his title.
He can be expelled, although that would be a drastic move to take about the man who set the party up.
Jean-Marie Le Pen was still firing on all cylinders on Wednesday.
"Mme Le Pen shold ask herself whether what she is doing is useful for the cause she claims to serve," he told RTL radio.
"I think the freedom to think, freedom of expression are precious and that the Front National must defend them."