The law of suretyship has just reached a decisive milestone regarding the assessment of manifest disproportionality. In a landmark ruling handed down on 26 November 2025, the Commercial Chamber of the Cour de cassation clarified the methods for calculating a surety’s indebtedness when the surety has already undertaken prior commitments.
Cass. com., 26 nov. 2025, n° 24-17.990, Publie au bulletin
1. The Dispute: A Challenge Based on Prior Liabilities
In January 2014, Ms. [X] stood as joint and several surety for SCI BCLP to guarantee the payment of rent under a commercial lease. Following the judicial liquidation of the tenant company in 2019, the lessor took action against the surety.
Ms. [X] then invoked the former article L. 341-4 of the Consumer Code, arguing that her commitment was manifestly disproportionate to her assets and income at the time of signing. She highlighted the existence of several suretyship commitments previously undertaken between 2004 and 2008, totalling more than 500,000 euros.
2. The Court of Appeal’s Position: A Formalistic Reading of the Caps
In its ruling of 4 June 2024 (Cour d’appel de Toulouse, 3rd chamber, 4 June 2024, n° 23_00214), the Cour d’appel de Toulouse ruled in favour of the surety. To establish disproportionality, the lower court judges added together the maximum amounts (caps) of the prior suretyship commitments as originally undertaken.
The Court of Appeal held that:
“the assessment of manifest disproportionality must be made based on the amounts already guaranteed by the surety at the time the disputed suretyship was entered into, irrespective of the sums for which the surety is ultimately called upon to pay”.
In other words, the Court of Appeal did not take into account any repayments that may have been made by the principal debtor on the debts previously guaranteed.
3. The Cour de cassation’s Reversal: The Primacy of “Amounts Still Owed”
The Cour de cassation, in its ruling No. 24-17.990 (published in the bulletin), quashed this decision for violation of the law. It holds that disproportionality must be assessed at the time of contract formation by taking into account the surety’s overall indebtedness, including that resulting from prior commitments, “provided that these suretyships have not been extinguished, in whole or in part”.
The Supreme Court sets out a very precise calculation rule:
“The amount of these commitments is understood as the sums still owed under the principal obligation they guarantee”.
It concludes that the Court of Appeal violated the applicable provisions by failing to take into account only “the amount of sums still owed under the guaranteed facilities” when assessing the surety’s liabilities at the date of the new commitment.
4. Analysis and Practical Implications for Practitioners
This decision provides major insights:
- Economic Reality vs. Formalism: The Court favours a concrete approach to indebtedness. As legal commentators explain, since the surety’s obligation is accessory in nature, any payment by the principal debtor mechanically reduces the surety’s indebtedness.
- Complexity of Proof: The burden of demonstrating disproportionality falls on the surety. Henceforth, the surety must precisely prove the outstanding principal balance of prior commitments at the relevant date (through amortisation schedules or account statements), which can prove complex several years after the fact.
- Greater Security for Creditors: For professional creditors, this ruling mechanically reduces the level of overall indebtedness that can be raised as a defence.
Although this case concerns the former Consumer Code, this assessment logic remains in principle transposable to the new article 2300 of the Civil Code introduced by the 2021 reform.
