How to Check a Subcontractor's Décennale Insurance Certificate
A valid *garantie décennale* certificate (France's mandatory ten-year structural liability cover for construction professionals) must state the insurer, contract number, validity period and covered scope of activity. A current-looking certificate is not enough if it does not cover the actual site start date.
The essentials
- The form and content of a garantie décennale certificate (France's mandatory ten-year structural liability cover for construction professionals) are set by article A.243-3 of the French Insurance Code (Code des assurances), under the arrêté du 5 janvier 2016.
- The certificate must be attached to the subcontractor's quotes and invoices, under article L.243-2 du Code des assurances.
- What matters is not the date the insurance contract was signed, but the site start date (date d'ouverture de chantier): it must fall within the validity period stated on the certificate.
- The certificate must specify the covered scope of activity; work not declared by the insured to its insurer is not covered, even if the document otherwise looks current.
- A non-compliant or out-of-scope certificate leaves the contracting party exposed if a claim later falls under the garantie décennale.
This article describes a mechanism specific to French construction law. It is relevant to any company contracting with subcontractors on projects governed by French law, even if the reader is based outside France.
What information must appear on a décennale certificate?
Article A.243-3 du Code des assurances sets out a precise list of required mentions. Without them, the document does not qualify as a proper certificate under article L.243-2.
In every case, the certificate must include: the insured party's company name and address; its unique identification number (SIREN/SIRET, per article D.123-235 du Code de commerce); the insurer's name and registered office address; the contract number; the validity period; and the date the certificate was issued. It must also reproduce wording required by the arrêté: the heading "Attestation d'assurance", the phrase "Assurance de responsabilité décennale obligatoire" in a central position, and a reference confirming cover applies within the framework of articles 1792 et seq. of the Code civil and articles L.241-1, L.241-2 and L.243-1-1 du Code des assurances.
A document limited to an insurer's logo and a general coverage statement, without these elements, does not meet the regulatory requirements — even if it is presented as a certificate.
Why does the site start date matter more than the contract signature date?
A certificate that is valid at the moment it is presented may still not cover the site in question. What matters is whether the site start date falls within the validity period stated on the certificate.
Article A.243-3 specifies that cover applies "to works for which the site opened during the certificate's validity period." The concept of ouverture de chantier (site start date) is itself defined in annex I of article A.243-1. In practice: a subcontractor may present a certificate that is currently valid at the time the contract is signed, while the site actually started months before the insurance policy took effect, or will start after it expires. In both cases, cover does not apply to that specific site, even though the certificate, read quickly, appears in order.
The useful check therefore compares two dates: the validity period stated on the certificate, and the actual site start date as declared to the client (maître d'ouvrage).
Is a subcontractor legally required to hold décennale insurance?
The insurance obligation applies to anyone whose liability can be engaged under the presumption set out in articles 1792 et seq. of the Code civil, which includes subcontractors carrying out construction works. Article L.243-2 du Code des assurances requires the certificate to be attached to quotes and invoices.
However, the contractual relationship between the main contractor and the subcontractor is not, as such, the source of this obligation toward the client: it is the nature of the works carried out by the subcontractor — whether or not they fall under the garantie décennale — that triggers the insurance obligation. In practice, main contractors systematically require the certificate before works begin, both as a contractual precaution and because their own liability can be pursued if a subcontractor turns out to be uninsured.
How do you check that the declared activity actually covers the work performed?
The certificate must specify the activity or activities declared by the insured to its insurer. An activity not mentioned is not covered, even if the certificate is otherwise valid and current.
This means comparing the activity description on the certificate against the actual nature of the work assigned under the subcontracting agreement. A waterproofing subcontractor whose certificate only mentions "structural works" without detailing waterproofing, or a subcontractor who has moved into a technique never declared to its insurer, carries a real risk of no cover in the event of a claim — independent of the document's formal validity. A certificate can also limit cover by project cost, geographic scope, or construction technique used: these limits must be checked against the actual characteristics of the project.
Table — required mentions and what to actually verify
| Mention on the certificate | What to verify in practice |
|---|---|
| Company name and address of the insured | Matches exactly the entity signing the subcontracting agreement, not a related entity |
| Unique identification number (SIREN/SIRET) | Identical to the number on the quote, the company registration extract, and the contract |
| Insurer's name and address | An identifiable insurance company, not only a broker's name |
| Contract number and issue date | Consistent with the other documents provided |
| Validity period | Covers the site start date, not just the date the contract was signed |
| Covered activities | Matches precisely the nature of the work assigned, not a neighbouring activity |
What should you do if the certificate does not cover the site in question?
If any of these points do not match, the certificate cannot be considered to cover the project, regardless of how it is formally presented. The most direct step is to ask the subcontractor for an updated or completed certificate, explicitly stating the activity and a validity period covering the actual site start date.
If doubt remains, the main contractor or client can seek confirmation directly from the insurer named on the certificate, whose full contact details are a mandatory mention. Without resolving this before works begin, the contracting party risks having to bear alone the consequences of a décennale claim that an upfront check would have flagged.
Frequently asked questions
Is a subcontractor required to hold décennale insurance?
The obligation depends on the nature of the work performed, not on subcontractor status as such. If the work falls under the décennale liability presumption (articles 1792 et seq. of the Code civil), the company performing it must be insured accordingly, whether it acts as main contractor or subcontractor.
Does the certificate need to be renewed every year?
The certificate states a validity period set by the insurer, which is not necessarily aligned with the calendar year. This period must be checked for every new project, rather than relying on a certificate obtained for a previous contract if its validity period has expired or does not cover the new site's start date.
Is a certificate linked to a group décennale policy valid?
Yes, if the certificate explicitly states this, along with the amount of the absolute deductible applicable to the insured under that group policy, as required by article A.243-3. The absence of this detail should raise concern about the document being incomplete.
What is the risk of accepting a non-compliant certificate?
There is no assurance that the subcontractor is actually covered for the site in question. If a décennale claim arises and the subcontractor turns out to be uninsured, the contracting party's own liability and financial exposure can be engaged, with no recourse against an insurer in the absence of valid cover.
What McLer does
McLer is an insurance brokerage specialised in corporate risk for the road transport and construction sectors. Based in the greater Paris region, McLer supports French SMEs and mid-sized companies in structuring, negotiating and managing their insurance programmes.
If checking subcontractor certificates, or structuring your own décennale cover, raises questions specific to your situation, a conversation with McLer can help clarify what applies to you, depending on your activity and markets.
This content is informational and does not constitute personalised advice.
Learn more: construction insurance in France.
Frequently asked questions
- Is a subcontractor required to hold décennale insurance?
- The obligation depends on the nature of the work performed, not on subcontractor status as such. If the work falls under the décennale liability presumption (articles 1792 et seq. of the Code civil), the company performing it must be insured accordingly, whether it acts as main contractor or subcontractor.
- Does the certificate need to be renewed every year?
- The certificate states a validity period set by the insurer, which is not necessarily aligned with the calendar year. This period must be checked for every new project, rather than relying on a certificate obtained for a previous contract if its validity period has expired or does not cover the new site's start date.
- Is a certificate linked to a group décennale policy valid?
- Yes, if the certificate explicitly states this, along with the amount of the absolute deductible applicable to the insured under that group policy, as required by article A.243-3. The absence of this detail should raise concern about the document being incomplete.
- What is the risk of accepting a non-compliant certificate?
- There is no assurance that the subcontractor is actually covered for the site in question. If a décennale claim arises and the subcontractor turns out to be uninsured, the contracting party's own liability and financial exposure can be engaged, with no recourse against an insurer in the absence of valid cover.