How to Prove Your Debt in France?

If you’re going to sue for a debt in France, prove it right.

Debt recovery is not only about choosing the right court and the right procedure. It is also about winning the proof battle: what you must prove, what your debtor must prove, what documents carry weight, and which “evidence” will be dismissed as self-serving.

In French debt litigation, many perfectly legitimate claims fail—not because the debt is imaginary, but because the creditor cannot demonstrate the obligation in a legally convincing way. This is especially true where the relationship was informal, the documentation incomplete, or the creditor relies too heavily on its own invoices and internal records.

This article explains the essential rules of evidence (preuve) in French debt recovery, with practical examples and tactical lessons you can apply before you start proceedings.

1. Who must prove what?

The creditor must prove the debt’s existence and amount

If you sue in France, the baseline rule is simple: the claimant must prove the claim. In a debt recovery case, that means the creditor must establish:

• the existence of the obligation (a contract, an order, a service, a delivery, etc.);

• the amount due (price, invoicing basis, penalties if applicable);

• and, where relevant, the performance you delivered (goods delivered, service performed).

A common illustration: a supplier claiming payment for goods must be able to prove delivery—and the debtor will try to dismantle that proof (for example by arguing that delivery notes have no signature or stamp: Cass. com., 1 April 2014, n° 13-11763).

The creditor does not have to prove non-payment

French law does not ask you to prove a negative that is practically impossible. So the creditor does not have to prove “I was not paid”. Instead:

• the debtor must prove payment (C. civ., art. 1353; see also Cass. civ. 1re, 13 Dec. 2005, n° 04-13818; Cass. civ. 3e, 9 March 2010, n° 07-18269).

In practice, a debtor cannot just say “I paid cash”. They must prove:

1. that a payment took place, and

2. that the payment corresponds to the specific invoice or debt being claimed.

This second point is a frequent trap: debtors sometimes show bank transfers or payments, but cannot connect them clearly to the invoice at issue—so they lose (e.g., client with multiple transactions: Cass. civ. 1re, 14 March 1995, n° 92-17413).

2. What counts as proof of payment?

The gold standard: a receipt (quittance)

A signed receipt or discharge issued by the creditor is one of the strongest payment proofs. There is no special formalism required—clarity + signature are the key.

But payment can be proven “by any means” (in many cases)

Payment is a fact, and French case law recognizes that facts can often be proven by any means (Cass. civ. 1re, 16 Sept. 2010, n° 09-13947). So even without a receipt, the debtor may use bank statements, correspondence, emails, etc.

A dangerous edge case: the “mistaken receipt”

If a creditor issues a document stating the loan or invoice was fully repaid, it is extremely difficult to “undo” later by merely claiming an internal error. The courts require strong proof to neutralize a discharge (e.g., bank claiming IT error: Cass. civ. 1re, 4 Nov. 2011, n° 10-27035).
Practical lesson: never issue a discharge unless your internal reconciliation is locked.

A cheque copy is not enough

A cheque is only payment if it is actually cashed. A debtor who only produces the front copy of a cheque does not prove payment (Cass. civ. 1re, 13 May 2014, n° 13-16846).

3. The rule that destroys weak files: you can’t create evidence for yourself

French law states: “Nul ne peut se constituer de titre à soi-même” (C. civ., art. 1363).
In plain language: your own documents don’t automatically prove your claim, because they are self-generated.

This is why many creditors lose when they rely on:

• invoices alone,

• internal spreadsheets,

• unilateral statements of account,

• “time sheets” written by the service provider alone.

Invoices alone may fail

A creditor cannot usually win based solely on its own invoices (classic reminder: Cass. civ. 2e, 23 Sept. 2004, n° 02-20497).

But the rule has nuance: if your invoices are supported by independent corroboration (delivery records, emails, acceptance, usage, partial payments, admissions, etc.), the whole file can become convincing.

A recent example illustrates this flexibility: proof of delivery may be established by any means, and a supplier can succeed by producing a combination of customer-account statements, invoices and delivery notes—even if not all delivery notes are signed (Cass. com., 26 June 2024, n° 22-24487).
Translation: the file wins, not one document.

Time sheets are not proof unless backed up

For professional services, internal “time sheets” have little value if they are not supported by concrete work product (drafts, letters, submissions, meeting notes, etc.). This was stated in the context of lawyers’ fees (Cass. civ. 2e, 4 Jan. 2006, n° 04-20136; and examples of acceptable supporting materials: Cass. civ. 2e, 24 May 2006, n° 04-13450).

4. Commercial vs. civil evidence rules: the debtor’s profile changes everything

This is one of the most important strategic points in French debt recovery.

A) Business-to-business (commercial debt): proof is largely free

Between merchants (commerçants), commercial acts can be proven by any means (C. com., art. L. 110-3). That means:

• emails, fax orders, delivery trails, accounting extracts, behavior, usage, etc., may be persuasive even without a signed contract.

Example: a fax order can be evidence if its authenticity is not seriously disputed (Cass. com., 13 May 1997, n° 95-14836).
Example: even an unregistered commercial document may still be opposable between merchants, because commercial proof is free (Cass. civ. 3e, 17 Dec. 2015, n° 12-26935).
Example: the date of an undated act can be proven by any means when existence is not disputed (Cass. com., 20 March 2024, n° 23-11844).

But “free proof” is not “careless proof.” Courts still assess credibility. When the debtor fights hard, the creditor who has only an invoice is exposed.

B) The artisan complication

An artisan is not automatically treated as a “merchant” under evidence rules. The text you provided highlights a major risk: when claiming more than €1,500 against an artisan, courts may require stricter civil-style proof because the artisan is not a merchant (e.g., signed delivery note held insufficient: Cass. civ. 1re, 18 Feb. 2009, n° 07-22076).
Practical lesson: don’t assume B2B equals “free proof” if the debtor is not legally a merchant.

C) Business-to-consumer (or suing a private individual): writing becomes critical above €1,500

If your debtor is a private individual, the French Civil Code evidence regime applies. For amounts above €1,500, a signed writing is normally required to prove the contract (C. civ., art. 1359; threshold set by decree).

If you have no signed contract, you may still succeed, but you typically need:

• a commencement of proof in writing (a written element coming from the debtor: email, letter, message, admission), plus

• additional corroborating evidence (C. civ., arts. 1361–1362).

What does not work if the amount is above €1,500 and there is no signed writing?

• Relying on witness statements alone (attestations) is generally not enough in that configuration.

A hard example: a plumber carried out works worth over €13,000 based on “word of honor” and social trust; the Court of cassation censured the decision that had accepted this approach—because the law requires writing above the threshold (Cass. civ. 1re, 29 Oct. 2014, n° 13-25080).
Similarly, additional works above €1,500 claimed from a non-merchant may fail absent writing or written commencement (Cass. civ. 3e, 17 Nov. 2021, n° 20-20409).

5. Can you use accounting records as evidence?

Using your own accounting

French law allows business accounting to be used as evidence in favor of the one who keeps it, but only between merchants and for commercial matters (C. com., art. L. 123-23).

In practice, accounting extracts are useful when the claim results from a complex running account or long-term calculation. Courts may accept them—especially if the debtor’s criticisms are weak (Cass. com., 27 April 1993, n° 91-16223).

A key case law reminder: courts cannot automatically dismiss a creditor’s claim just because the creditor provides invoices and accounting documents—between commercial companies, judges must examine those documents (Cass. com., 1 July 2020, n° 18-22067).

Using the debtor’s accounting

There is also a theoretical route: the debtor’s own books can be used against them (C. civ., art. 1378), and courts can consider them even if irregularly kept. But in practice, requests for judicial communication of accounting books are rare and can slow the procedure. Still, in high-stakes disputes, it can be a powerful lever.

Be careful: an expert-comptable cannot prove their fees by relying on the client’s accounting if the expert themselves created those documents (Cass. civ. 1re, 6 May 1997, n° 95-15420).

6. Does silence after receiving an invoice equal acceptance?

Not automatically.

French law is clear: silence does not, by itself, mean acceptance (and this principle is now in the Civil Code: C. civ., art. 1120). That means:

• the mere fact the debtor did not contest the invoice immediately does not automatically prove your claim.

However, silence can become meaningful depending on the context: business practice, longstanding relationship, prior deliveries, repeated invoices, and especially when the debtor only starts “complaining” once sued.

A classic scenario: a merchant receives goods and stays quiet; only three months later—after a registered demand for payment—do they suddenly claim quality issues. Courts may treat this as dilatory contestation and condemn payment (Cass. com., 31 May 1983, n° 81-16350).

Practical lesson: preserve evidence showing the debtor had time and opportunity to object but did not.

7. Witness statements (attestations): useful, but not a magic key

Attestations are admissible, but their strategic value depends on the case.

They are most useful to establish facts (presence at a meeting, delivery circumstances, acceptance behavior, etc.). They are less effective to prove a consumer contract above €1,500 when there is no writing.

French procedure provides a framework for attestations (C. proc. civ., art. 202): identity details, relationship to parties, awareness it will be used in court, and the penal risk of false statements—plus ID copy. But formal defects do not automatically nullify them (Cass. civ. 2e, 18 March 1998, n° 95-16480).

Important nuance: a court cannot deny all probative value to an attestation merely because someone filed a criminal complaint alleging a false attestation (Cass. civ. 2e, 16 Dec. 2021, n° 20-15875).

8. “Modern evidence”: SMS, business secrecy, and even covert recordings

French courts have become more pragmatic about real-life proof.

• SMS can be admissible evidence because the sender cannot ignore that messages are stored on the recipient’s phone (Cass. soc., 23 May 2007, n° 06-43209).

• Business secrets (secret des affaires) do not absolutely block production. A protected document may be produced if it is indispensable to the right to proof and if the infringement is strictly proportionate (Cass. com., 5 June 2024, n° 23-10954).

• Illicit or disloyal evidence (e.g., clandestine recordings) is not automatically excluded. The judge must assess whether admitting it undermines the fairness of the proceedings; it may be admitted if indispensable and proportionate (Cass. ass. plén., 22 Dec. 2023, n° 20-20648).
  This does not mean “anything goes”—but it does mean French civil courts now sometimes accept evidence that older approaches would have rejected, especially where the right to proof is otherwise impossible.

9. What a “clean” debt recovery evidence pack looks like

You don’t need perfection. You need coherence. Ideally, your file should tell a simple story:

1. Agreement / order

   • signed order form or signed quote (best)

   • or emails / acceptance trail

2. Performance

   • delivery note signed and dated (best for goods)

   • service acceptance / work reports / meeting minutes

3. Price and invoicing

   • invoice(s) consistent with agreed price or a clear calculation basis

4. Debtor behavior

   • absence of timely protest

   • partial payments

   • admissions / promises to pay / proposed schedules

5. Formal chasing

   • reminders + formal notice (even though reminders alone do not interrupt limitation, they support seriousness and context)

A single weak document rarely wins. A consistent bundle often does.

10. The most common mistakes creditors make in France

Here are the failures that repeatedly destroy cases:

• Suing with invoices only, without proving the order and/or delivery.

• Assuming “the debtor must prove they didn’t owe it” (wrong: you must prove the debt; they prove payment).

• Treating artisans as if they were always merchants for evidence purposes.

• Doing significant work for a consumer without a signed quote when the value exceeds €1,500.

• Issuing receipts / discharges too easily, then trying to retract them.

• Accepting vague payments without identifying which invoice they settle.