Lump Sum Contract: The Client's Silence Constitutes Acceptance of the Final Account

In Landerneau, a public works contractor spent months enduring delays, poor coordination and constant changes on a construction site. At the end, he sent his final account, claiming nearly €60,000 for additional works and compensation. The client, a SCI (property investment company), did not respond. Radio silence. Then, it took legal action. Too late, says the Court of Cassation: by not responding, it accepted the account. Result: it must pay.

Are you a property owner, developer or contractor? This decision directly concerns you. Because it establishes a simple rule: in a lump sum contract, the client's silence in the face of a detailed final account constitutes acceptance. And subsequent legal proceedings do not affect the enforceability of the sums.

Let us decipher this case together, its facts, its reasoning and above all what it changes for you, practically, whether you are in Guipavas or elsewhere.

The facts: a story that happens every day

The SCI Lyon Islands, as client, awarded two lump sum works contracts to a contractor. The site, located in a new development, turned into a nightmare: deadlines slipped, coordination between trades was catastrophic, delivery scheduling was constantly changed. In short, complete disorganisation.

The contractor incurred significant additional costs. He therefore prepared his final accounts, in accordance with AFNOR standard NF P 03.001 (December 2000 edition) referred to in the contracts. In these accounts, he detailed precisely: on the one hand, the contractual breaches (delays, poor coordination, changes, disorganisation); on the other hand, the direct financial consequences. For the first contract, he claimed €58,938.49 including VAT for additional works not formalised by a variation order. For the second, he distinguished the balance of the original contract and the variation works.

What did the SCI do? Nothing. It did not respond to the accounts. Not a letter, not a challenge. Then, it initiated legal proceedings against the contractor, without having complied with the contractual dialogue phase. The contractor, for his part, claimed in court payment of the sums due on the basis of the unchallenged accounts.

The Court of Appeal ruled in favour of the contractor: in the absence of a contradictory response within the contractual period, the client is deemed to have accepted the final account. Judgment ordering payment. The SCI appealed to the Court of Cassation. But the Court of Cassation dismissed its appeal: the reasoning was correct. Silence constitutes acceptance, and the proceedings initiated by the SCI do not affect the enforceability of the sums.

The reasoning of the court — broken down

The Court of Cassation relies on the general law of contracts (the former Article 1134 of the Civil Code, now Article 1103: “Contracts lawfully formed take the place of law for those who have made them”) and on AFNOR standard NF P 03.001, which provides for a procedure for closing accounts. Concretely, the lump sum contract requires that, at the end of the works, the contractor sends a final account summarising all his claims. The client has a period to respond, point by point, accepting or challenging each amount. If he does not respond, the standard and case law consider that he implicitly accepts.

In this case, the accounts were particularly detailed: they listed the breaches (delays, poor coordination, constant changes to scheduling, site disorganisation) and the financial consequences. The SCI could not therefore claim ignorance of the content. By not responding, it let the period expire. The Court of Appeal was therefore entitled to legally infer acceptance. And the Court of Cassation validates: “the client, having refrained from providing a contradictory response [...] was deemed to have accepted the final account”.

This decision confirms consistent case law: in private works contracts, the client's silence in the face of a detailed final account constitutes acceptance. It also reminds that the initiation of subsequent legal proceedings does not suspend the enforceability of sums already accepted. In other words: you cannot challenge in court what you have already let pass without reacting.

The decision is important because it reassures contractors: a well-drafted account, with precise details, obliges the client to respond. If he does not, he pays. Conversely, it warns clients: do not neglect the account-closing phase, otherwise you may have to pay sums that you nevertheless contest.

What this changes for you — practically

For the contractor: you have every interest in carefully preparing your final account. The more precise it is, the more it forces the client to react. If he does not respond, you can claim payment of the sums without having to prove the merit of each line. Example: in Guipavas, an electrician recovered €12,000 for additional works simply because the developer had not responded to his account within 30 days. Without this decision, he would have had to litigate for months.

For the client (property owner, developer, SCI): you must imperatively respond to each final account, even if you contest everything. A simple letter saying “I contest all amounts” may suffice to avoid tacit acceptance. But if you let the period pass, you will be ordered to pay, even if you have good reasons to contest. And legal proceedings will not save you.

For the individual building a house: if you are the client of an individual house, the same principle applies. Your construction contract (CCMI) or lump sum contract often contains an account-closing clause. Do not neglect the contractor's final account. Respond within the deadlines, even just to say you contest. Otherwise, you risk having to pay sums you consider undue, without being able to contest them later.

In summary: silence is a trap for the client, and a weapon for the contractor.

Four tips to avoid this type of dispute

• For the contractor: draft a comprehensive and detailed final account. List each breach, each additional cost, with dates, amounts, references to documents. The more precise it is, the more the client is obliged to respond. In case of silence, you win.
• For the client: never leave a final account unanswered. Even if you consider the claims unfounded, respond in writing within the contractual period (often 30 to 60 days). A simple letter of global challenge suffices to avoid tacit acceptance. Keep proof of response (registered letter, email with read receipt).
• For both parties: strictly follow the contractual procedure. AFNOR standard NF P 03.001 or the contract clauses set a timetable: final account, response, exchanges. Respect each step. Legal proceedings cannot substitute for this phase.
• For individuals: get professional assistance for the snagging and account closing. An architect, project manager or lawyer can help you check the final account and respond correctly. The investment is small compared to the risk of having to pay €60,000 without being able to discuss.

Further reading: related case law and developments

This decision is part of a consistent line of the Court of Cassation. We can cite the judgment of 9 October 2019 (No. 18-18.501) which, in another lump sum contract, had already ruled that failure to respond to the final account constituted acceptance. The solution is therefore well established.

A divergence previously existed on the requirement for precision of the account. Some Courts of Appeal required a detailed breakdown of sums. Here, the Court of Cassation validates an account that clearly distinguishes the items (original works, variations, additional works) and the breaches. The trend is therefore towards a certain flexibility, as long as the account is sufficiently explicit to allow a challenge.

In the future, we can expect courts to continue to sanction clients who neglect the account-closing phase. AFNOR standard NF P 03.001 remains a reference, but even in its absence, judges apply the general principle of contractual good faith (Art. 1104 Civil Code).

In practice: what to do

FAQ:

1. My contractor has sent me a final account, what should I do?
Respond in writing within the period provided in the contract (usually 30 days). Even if you contest everything, a letter of challenge suffices. Do not remain silent.

2. I received a very detailed account, can I still challenge it after the deadline?
No. After the deadline, you are deemed to have accepted. You can no longer challenge the principle or the amount, unless you can prove a defect of consent (fraud, mistake), which is very difficult to prove.

3. Can I initiate legal proceedings to contest the account after leaving it unanswered?
No, as this judgment reminds: legal proceedings have no effect on the enforceability of the sums. You will pay first, and cannot contest later.

4. What if I did not receive the account? The contractor claims he sent it.
Check your post, emails. If you received nothing, contest receipt. But if the contractor proves dispatch (registered letter, email with receipt), you will be deemed to have received it. So it is better to be reactive.

5. My contract does not mention AFNOR standard, am I concerned?
Yes, because the principles of good faith and contractual procedure apply. Judges consider that silence constitutes acceptance as soon as the contract provides for an account-closing phase, even without reference to a specific standard.

Do you find yourself in a similar situation? A first 30-minute consultation with Maître Zakine (€45) could save you months of litigation — and often much more. Book an appointment →