French far-right leader Marine Le Pen said that her National Rally (RN) party is being "assassinated" by judges who blocked €2m (£1.7m) of public funding for it.
The RN - formerly the National Front (FN) is condemned for misusing €7m of European Parliament funds intended to pay MEPs' assistants in Brussels.
French prosecutors suspect that the RN used EU funds to pay staff in France.
Le Pen and 7 RN colleagues are members of the French parliament.
In a tweet (in French) on Monday Ms Le Pen said: "Two judges have decided, in violation of the presumption of innocence, without any court ruling, to assassinate France's leading opposition party."
Le Pen said seizing the RN's public subsidy "puts democracy at risk - it's also a matter for all the parties". French banks have previously refused to lend to her party.