Pourvoi n°24-10.653 | Cour de cassation

Following an Urssaf audit covering the years 2015 and 2016, a company was served with several assessment notices, including the reinstatement of business expenses in the base for social security contributions. Challenging this assessment, the company submitted, for the first time before the Court of Appeals, new evidence intended to justify the deductibility of those expenses. The company argues that, pursuant to Article R. 142-1 of the Social Security Code and Article 563 of the Code of Civil Procedure, a taxpayer may present new arguments, new documents, or new evidence on appeal to support the claims it had already submitted at the trial court level.

The Court of Cassation dismissed the appeal. It noted that, while the taxpayer may in principle submit to the court all documents relevant to the success of their claims, this right is subject to limitations when the burden of proof regarding the accuracy of social security declarations rests with the taxpayer. With regard to the deduction of business expenses, supporting documents must be provided during the audit or the adversarial phase to enable Urssaf to verify compliance with social security legislation. The Court of Cassation reiterates that, for the purposes of applying Articles L. 213-1 and L. 243-7 of the Social Security Code, contributors must retain evidence demonstrating the accuracy of their declarations so that collection agencies can verify their completeness, compliance, and consistency. With regard to the deduction of business expenses, supporting documents must therefore be provided during audits or the adversarial phase to enable URSSAF to verify that the conditions for applying social security legislation are indeed met. Since the company did not provide this evidence to URSSAF, it cannot submit it for the first time before the judge to whom it has appealed to challenge the assessment.

This ruling applies the legal principle established by the Court of Cassation in its decision of September 4, 2025 (Cass. 2^nd Civ. 4-9-2025 No. 22-17.437 FS-B) regarding the submission of new evidence in litigation over URSSAF assessments. In this landmark decision, the High Court held that a taxpayer challenging an assessment may, in principle, submit to the court any document relevant to supporting their claims. However, this principle does not apply in two cases: first, documents expressly requested by Urssaf during the audit that the taxpayer failed to submit are inadmissible before the court; and second,

documents that the taxpayer was unable to produce during the audit to demonstrate the accuracy of the social security declarations they filed, even though the burden of proof regarding the accuracy of such declarations rests with them—which is particularly the case with regard to the deduction of business expenses.

The June 25, 2026, ruling falls precisely within this second exception. The Court of Cassation confirms that supporting documents required to claim the deduction for professional expenses must be produced either during the audit phase or during the adversarial proceedings. Otherwise, they are inadmissible before the court. This ruling reinforces the scope of Urssaf audits by reiterating that the adversarial hearing cannot be deferred to the litigation stage when the regulations expressly place the burden of proof regarding the reported items on the taxpayer. It thus confirms that the rules of evidence applicable to collection litigation remain largely determined by the specific characteristics of the social security reporting system and by the requirements specific to the audits conducted by Urssaf.ours de la procédure contradictoire. À défaut, ils sont irrecevables devant le juge. Cette solution renforce la portée du contrôle Urssaf en rappelant que le débat contradictoire ne peut être différé au stade contentieux lorsque la réglementation met expressément à la charge du cotisant la justification des éléments déclarés. Elle confirme ainsi que les règles de preuve applicables au contentieux du recouvrement demeurent largement déterminées par les spécificités du système déclaratif de la sécurité sociale et par les exigences propres au contrôle exercé par l’Urssaf.