Paris(CNN) Marine Le Pen, the leader of France's National Front party, has been formally placed under investigation in connection with a corruption scandal, a spokesman for the far-right party told CNN on Friday.
She will appeal against the decision on Monday, National Front press director Alain Vizier said.
In the French criminal justice system, a "formal investigation" is the step before filing charges.
Catherine Griset, Le Pen's chief of staff, was formally charged as part of a probe into the alleged misuse of EU funds in February. Le Pen's bodyguard, Thierry Legier, was also questioned.
The controversy shadowed Le Pen's campaign for the French presidency.
She lost in the second round to centrist Emmanuel Macron, who was sworn in as President in May.