Internal investigations by the European Anti-Fraud Office (OLAF) into the right-wing French party Front National/Rassemblement National and its party leaders have led to court rulings.

On 31 March 2025, a criminal court in Paris found Marine Le Pen (daughter of former party leader Jean-Marie Le Pen and MEP between 2004-2017) and other members of the party guilty of embezzlement of EU funds. The central allegation in the trial was that Le Pen's party, Rassemblement National, had received money from the European Parliament for parliamentary assistants who were fictitiously listed as assistants of MEPs, but had worked in reality partly or entirely for the party. Relevant evidence was gathered by OLAF and OLAF's findings were incorporated into the judicial proceedings in France.

On 16 July 2025, the General Court of the EU upheld a decision by the Secretary-General of the European Parliament to recover over €300,000 in EU funds wrongfully received by the late party leader Jean-Marie Le Pen. In this case (T-480/24), OLAF found that Le Pen had wrongfully claimed reimbursement for personal expenses as parliamentary expenses, including newsletters, pens, business cards, ties, umbrellas, kitchen scales, table clocks, smart bracelets, virtual reality glasses and 129 bottles of wine. Specifically, the case concerned the years 2009 to 2018, when Jean-Marie Le Pen was a Member of the European Parliament.

In the lawsuit filed before his death, Le Pen argued that the recovery violated the principles of legal certainty and protection of legitimate expectations, as well as the right to a fair trial. Following the death of Mr Le Pen on 7 January 2025, his daughters, as his heirs, pursued the pending proceedings. The Court rejected the arguments and held, inter alia, that the investigations led by OLAF and the subsequent administrative procedure by the EP were completely correct. Mr Le Pen was regularly informed of all the facts alleged against him and invited to submit his observations.