Indemnisation: the proportional rule, an obligation for the judge

The impact of inaccurate statements in insurance: legal analysis and recent cases.

The accurate declaration of risk by the insured is a fundamental pillar of the insurance contract, but its practical implications are sometimes misunderstood. This article revisits the rules applicable in case of omission or inaccuracy, as well as the latest judicial decisions that clarify its boundaries.

Proportional reduction: how does article L.113-9 apply?

When an insured does not declare the risk exactly or completely, the indemnity paid is reduced proportionally to the ratio between the premium actually paid and the one that should have been paid. This is a well-known rule, but its application is sometimes misunderstood.

Declarative obligations and increased risk

Two articles outline the obligations of the insured:

L.113-2: obligation to respond accurately to questions asked during subscription.
L.113-4: obligation to declare any worsening of the risk during the contract.

Clause L.113-10: What sanction in case of omission?

In so-called "food" policies, a clause may provide for a flat-rate reduction of 50% of the compensation in case of omission of declaration. If this clause is present, it replaces the application of article L.113-9 (Cass. 3rd civ., 26 Nov. 2020).

What the latest court decisions say

CA Paris, June 14, 2023 : the reduction must be calculated based on the premium that would have been due if the risk had been correctly declared, and not fixed in a lump sum manner.
CA Grenoble, April 13, 2023 : in the absence of clause L.113-10 and if the contribution is a lump sum, only the proportional reduction of L.113-9 applies.

Focus on the decision of July 10, 2025 (Court of Cassation, 3rd Civil Chamber, No. 23-20.239)

The Court of Cassation recalls that as soon as a non-fraudulent inaccurate statement is established, the judge must apply the proportional reduction provided for in Article L.113-9. Even if the file does not contain all the numerical elements, the judge cannot refuse to apply the rule: he must reopen the debates to obtain the necessary information (premium paid vs premium due).

This position is consistent with established case law:

Civil 1st, June 6, 2000: the burden of proof of the reduction rate lies with the insurer.
Civil Code, 12 September 2013: the judge cannot refuse to assess a debt recognized in principle.
Civil Code, 2nd edition, October 14, 2021: the judge must assess the damage even without all the justifications.
Com., 19 Nov. 2013: obligation for the judge to determine the amount of a debt acquired.

In summary: the judge has the obligation to apply the proportional reduction as soon as the principle is established, even if it means requesting specific numerical details. The insurer remains responsible for providing the calculation elements.

Warranty conditions in construction insurance: what you need to know

Dans un Decision of March 7, 2024 (Court of Cassation, 3rd Civil Chamber, No. 22-17.200) , la Cour de cassation rappelle un principe fondamental en assurance construction obligatoire (DO, CNR, RC The standard clauses provided for in Article A.243-1 of the Insurance Code cannot be limited by "guarantee conditions" added to the contract.

For example, observations made by a technical design office on a construction site cannot be used to restrict the warranty. At best, they fall under:

from a contractual obligation
or an increase in risk, to be declared according to articles L.113-2 and L.113-4.

But under no circumstances can they justify a warranty exclusion or non-compensation.

In clear terms : technical conditions cannot restrict legal guarantees. Only the rules for declaring and aggravating the risk can have an impact, and they are regulated by articles L.113-8 to L.113-10.

Need to know more?

Contact our Director of Construction & Energy

Raphael Cerda

Head of Construction & Energy

Raphael Cerda

Head of Construction & Energy

With nearly 20 years of experience in construction insurance, Raphaël has held increasingly responsible positions at Bouygues Construction, Marsh, and Satec where he was head of Construction and Real Estate. He now joins Howden France to lead the development of the Construction and Energy Product Line on an international scale. Recognized for his negotiation skills and strategic vision, Raphaël will contribute to positioning Howden France as a leading player in the construction and energy insurance market.

Specific expertise: Decennial, Waterproofness, Real Estate, Large Projects

Degrees:
- MASTER Degree IAP / La Sorbonne
- MASTER Degree Insurance Law / La Sorbonne
- Executive MBA / PSL Paris Dauphine
- Executive MBA / UQAM Montreal