The founder of France's far-right National Front Jean-Marie Le Pen said party might not win as many seats as expected in next month's parliamentary election because of Marion Maréchal-Le Pen's decision to leave politics | Kenzo Tribouillard/AFP via Getty Images Jean-Marie Le Pen: ‘Marine could pay dearly’ for Marion’s withdrawal The National Front could lose seats in next month’s legislative election, party founder warns.

The founder of France's far-right National Front said the party might not win as many seats as expected in next month's parliamentary election because of Marion Maréchal-Le Pen's decision to leave politics, Le Parisien reported Thursday.

"This departure will weigh heavily [in the election]," Jean-Marie Le Pen said, adding that his daughter Marine Le Pen, the current leader of the party, "could pay dearly."

Marion Maréchal-Le Pen — who is Marine's niece — is popular with voters in the party's southern strongholds. Citing personal reasons, she announced her retirement from politics on Wednesday, days after her intentions were leaked to Le Figaro.

Jean-Marie, who is close to Marion, criticized the move, calling it a "desertion." In the Le Parisien interview, he conceded that he may have overreacted. "When I see her motives that she explained, especially regarding her personal life, I begin to understand."

But he said the decision to step down had "grave consequences" for internal party politics.

Jean-Marie sided with Marion against her rival Florian Philippot, the National Front's vice president and who is responsible for the party's Euroskeptic policies.

The National Front "will never be the party of the Philippot brothers," Le Pen said, referring to Florian and his brother Damien, also a National Front stalwart.