Marine Le Pen, head of France’s far-right National Front, has said the party’s long-time bank, Societe Generale, has closed its accounts.
She said the move amounts to a "banking fatwa" to suffocate the party.
Ms Le Pen claimed at a news conference today that the move is purely political and endangers the democratic process.
She said a legal complaint would be filed against Societe Generale, one of France’s largest banks, as well as against HSBC, her personal bank, which also allegedly shut her out.
Societe Generale denied in a statement that the closing of National Front accounts was political, saying such moves "depend purely on banking reasons".
It gave no reason for the closing of the party account and related accounts.
Ms Le Pen refused to disclose how much money was in the accounts, which she said included those of about 15 National Front federations around France.
What Ms Le Pen called the "banishment" of her party from the banking system is the latest in a multitude of financial, judicial and political woes for the National Front, which was refused loans for campaigning for French and legislative elections this year.
Following Front National press conference: Societe Generale group’s decisions on opening or closing a bank account depend purely on banking reasons and in respect of all regulatory requirements, without taking into account any political consideration.https://t.co/ULknXZ5Wng— Société Générale (@SocieteGenerale) November 22, 2017
Ms Le Pen lost the May presidential election to centrist Emmanuel Macron, with whom she raised the banking issue during a meeting this week as he received party leaders.
The National Front was able to reopen an old account at Credit du Nord bank, a subsidiary of Societe Generale.
However, it is deprived of cheque books, members and supporters are unable to pay dues or donations on the party site and it cannot make automatic withdrawals, such as to pay officials, Ms Le Pen said.
Such measures have upset "the normal functioning of a party ...", Ms Le Pen said.
"We are in the presence of an attempted suffocation of an opposition movement."