Renault disputes legality of diesel case procedure again

Renault challenges legality of procedures in long-running diesel investigation, plans new appeal to France’s Court of Cassation after investigating chamber’s refusal.

Renault is again challenging the legality of the procedures in the French diesel case: after the investigating chamber declined to apply the Court of Cassation’s jurisprudence, the company says it will file a new appeal to the Cour de cassation. In its 17 September 2025 statement, Renault frames the move as a defense of its right to a fair, adversarial and impartial process.

According to the company, on 23 April 2024 the Court of Cassation confirmed the legitimacy of its appeal and recognized violations of its rights, quashing a prior ruling; the remand jurisdiction then refused to follow that position, prompting Renault to return to the high court.

On the merits, Renault maintains it committed no offense, says its vehicles are not equipped with defeat software for emission controls, and notes that all models were homologated under the applicable French and EU rules at the time of sale.

Background: the judicial investigation was opened on 12 January 2017; on 8 June 2021 Renault S.A.S. was placed under formal investigation (*mise en examen*) on a charge of deceit, with a €20 million bail and a €60 million bank guarantee, while the company emphasized the presumption of innocence.

What *mise en examen* means: it is a decision by an investigating judge during a judicial inquiry when there are “serious or consistent indications” of involvement; it grants defense rights and is not a conviction.

Cautious procedural outlook: a new appeal to the Court of Cassation triggers a review of law, not facts. The court may quash a decision for legal errors and generally remand the case (sometimes without remand). Timelines and consequences depend on the court’s findings.

For broader context: in July 2025 the Paris prosecutor’s office requested a third trial for aggravated deception in the “Dieselgate” probe concerning Renault; the company continues to deny wrongdoing.