A top aide to French far-right leader Marine Le Pen quit the National Front on Thursday, laying bare a deep split over Europe and immigration after the party's election defeat this year.

Florian Philippot, architect of the party's pledge to quit the euro and of Le Pen's drive to detoxify the National Front (FN) brand among voters, announced his departure on France 2 television, after Le Pen stripped him of most of his responsibilities.

"Listen, I don't like being ridiculed, I've never liked having nothing to do, so sure, I'm quitting the National Front," the party's 35-year-old vice president said. 

Philippot said he believed that the party's attempt to reposition itself after its disappointing performance in both the May presidential and June parliamentary elections masked "a terrible backward slide" towards the FN's hardline past.

"I saw how things were developing negatively these past weeks, that maybe I wouldn't have a place in the project and thus they needed a pretext," Philippot said.

Le Pen said she was "not overjoyed about Florian leaving" but assured: "The Front will get over it, no problem."

She accused her former right-hand man of "playing the victim" and said his accusations of a rollback towards the extremism of the party's beginnings "made absolutely no sense" and were "partly defamatory".

She insisted that the party's policies were still under debate and would be decided only at its next congress.

She also sought to stamp out the speculation swirling about her own future since her defeat in her second bid for president.

"I am the strongest and best placed" for the next presidential election in 2022, she said.

- Charting his own path - 

The media-savvy Philippot, who became the face of a more moderate FN, had been on a collision course with the party leadership since the presidential election, won by centrist Emmanuel Macron.

Many rivals in the party blamed him for driving a plan to scrap the euro and bring back the French franc -- despite polls showing French voters being attached to the common currency.

Le Pen floundered badly in the final presidential debate on the issue and ended up trailing Macron in the election run-off, garnering just 33.9 percent of the vote.

FN hardliners have seized on her defeat to try to refocus the party on its stock themes of immigration and security -- issues that took a back seat to economic nationalism while Philippot had Le Pen's ear.

Seeing his influence in the party wane, Philippot began to chart his own path, creating his own Patriots association in May.

Accusing him of a conflict of interest, Le Pen on Wednesday took away his responsibility for strategy and communication, leaving him with no specific brief.

Another Le Pen advisor, economist Philippe Murer, also announced his resignation Thursday, saying that he too disagreed with the new direction being proposed by Le Pen.

"The FN will talk mostly about mass immigration, a real problem for France, but it will not propose a real programme to defend the middle and lower classes," he wrote on Twitter.

He blamed influential FN hardliners including MP Gilbert Collard; Robert Menard, the mayor of the southern town of Beziers; and Le Pen's partner Louis Aliot, also an MP, for leading a campaign against Philippot. 

Aliot launched a blistering attack on Philippot on Twitter on Thursday, accusing him of being "vain and arrogant" and of "trying to muzzle our ability to debate."