Payment demand in Belgium: reminder and mise en demeure

Quick answer

In Belgium, a mise en demeure (formal notice, art. 5.231 C. civ.) is a clear demand to pay. No form is required, so a standard or tracked letter is valid, but you must prove that it reached the debtor. From then on, legal interest runs: 4.5% a year in 2026. Between businesses, interest runs automatically from the due date at 10.5% in 2026, plus a flat €40. If you are a business and your debtor is a consumer, send a free first reminder and wait 14 days before charging anything. Your own letter does not stop the limitation period, and the injonction de payer (summary payment order) needs a registered letter with acknowledgement of receipt or a bailiff first.

This guide covers sums already due from a company or individual in Belgium: an unpaid invoice, an agreed refund, or a loan not repaid. It is general information, not legal advice. For a rental deposit, see tenant letters in Belgium; to complain about goods or a service, see formal complaints in Belgium; to end a contract, see cancelling a contract in Belgium. Belgian law imposes no language on a private letter (art. 30 of the Constitution), so the French examples below are valid in Flanders too, although a Flemish debtor may answer in Dutch.

Check the claim and who owes it

Know why the money is owed and when it fell due, and keep the contract, invoice, transfer records and messages. Three regimes apply:

• Business to business, including a freelancer invoicing a company: if no term was agreed, payment is due 30 calendar days after the invoice is received, and agreed terms may not exceed 60 days (art. 4 de la loi du 2 août 2002 concernant la lutte contre le retard de paiement dans les transactions commerciales).
• Business to consumer: Book XIX of the Code de droit économique (CDE), in force since 1 September 2023, limits what you can charge.
• Between private individuals, such as a private loan: only the general civil law applies.

The new Civil Code rules cited here apply to contracts concluded from 1 January 2023; an older contract stays under the old Civil Code unless the parties agreed otherwise (art. 64 de la loi du 28 avril 2022).

Consumer debtors: send the free first reminder

If you are a business and your customer is a consumer, a clause on interest or a lump-sum indemnity (clause indemnitaire) applies only after a first reminder and at least 14 calendar days (art. XIX.2 CDE). The first reminder is free and must be sent on a durable medium, such as paper or email. For a paper reminder, the 14 days start on the third working day after sending; for an email, on the next day. It must state:

• the amount still due, and the indemnity that will be charged if it is not paid within 14 days;
• your name and enterprise number (numéro d’entreprise);
• the product or service and its due date;
• the 14-day period before any costs, interest or indemnity.

After the 14 days, you may claim only what the contract expressly provides for, within caps: interest of at most 10.5% a year in 2026, and a lump sum of at most €20 for a balance up to €150; for a balance from €150.01 to €500, €30 plus 10% of the amount between €150.01 and €500; for a balance above €500, €65 plus 5% of the amount above €500; never more than €2,000 (art. XIX.4). You must be able to prove that you complied (art. XIX.2, § 5), so keep a dated record of the reminder. The bold “Cette lettre ne concerne PAS une citation au tribunal” notice is required only from debt collectors, lawyers and bailiffs: do not add it yourself.

Objet : Premier rappel — facture n° [numéro de facture] du [date de la facture]

Madame, Monsieur,

Sauf erreur de ma part, la facture n° [numéro de facture] du [date de la facture], relative à [description du produit ou du service], échue le [date d’échéance], n’a pas été réglée. Le montant restant dû s’élève à [montant] euros.

Ce premier rappel est gratuit. Vous disposez d’un délai de quatorze jours calendrier, qui commence à courir le troisième jour ouvrable suivant l’envoi du présent rappel, pour régler ce montant sans frais par virement sur le compte [IBAN] au nom de [titulaire du compte], avec la référence [référence].

À défaut de paiement dans ce délai, [l’indemnité forfaitaire de [montant] euros et les intérêts de retard au taux de [taux] % par an] prévus par [les conditions générales ou le contrat] pourront vous être réclamés, conformément à l’article XIX.4 du Code de droit économique. Aucun frais, intérêt ni indemnité ne vous sera réclamé avant l’expiration de ce délai.

Si vous avez déjà effectué ce paiement, je vous remercie de ne pas tenir compte du présent rappel. Si vous contestez ce montant, je vous remercie de m’en indiquer les motifs par écrit. Les pièces justificatives sont à votre disposition sur simple demande.

Veuillez agréer, Madame, Monsieur, l’expression de mes salutations distinguées. [Prénom et nom ou dénomination] Numéro d’entreprise : [numéro d’entreprise] [Adresse]

If your contract provides for no interest or indemnity, delete the third paragraph: you can then claim only legal interest, from a later mise en demeure (art. 5.240 C. civ.).

Put the debtor on notice: mise en demeure

A mise en demeure is a unilateral act by which you notify the debtor, clearly and unambiguously, that you demand payment; the law, the contract or good faith may require you to give a reasonable period (art. 5.231 C. civ.). You may send it shortly before the due date, but it takes effect only once that date has passed (art. 5.232). None is needed if the debtor has said it will not pay, or the law or contract makes it in default when the due date passes (art. 5.233). From the mise en demeure, legal interest is due without proof of loss (art. 5.240): 4.5% a year in 2026, a rate published each year in the Moniteur belge. Interest itself earns interest only after a written mise en demeure, and only for interest owed for at least a full year (art. 5.207). No minimum deadline applies; 8 to 15 days from receipt is common practice.

Between businesses, no demand is needed: interest is due automatically from the day after the due date, at the ECB reference rate plus 8 points, rounded up to the next half point (10.5% a year for both halves of 2026), plus a flat €40 and reasonable further recovery costs (art. 5 and 6 de la loi du 2 août 2002). A clause excluding late interest is treated as manifestly abusive, and one excluding the €40 is presumed to be, so the judge can set it aside (art. 7). A penalty clause that is manifestly unreasonable can be reduced by the judge (art. 5.88 C. civ.).

In the example, keep the interest paragraph that applies; for a contract concluded before 2023, the old Civil Code applies, so delete the references to articles 5.231 and 5.240. For a consumer, send it only after the first reminder and its 14 days, and claim only the amounts announced in that reminder.

Objet : Mise en demeure de payer — [facture n° [numéro] du [date] ou autre référence]

Madame, Monsieur,

En vertu de [contrat, bon de commande ou facture] du [date], vous êtes tenu(e) de me payer la somme de [montant] euros au titre de [objet de la créance], exigible depuis le [date d’échéance]. À ce jour, j’ai reçu [montant déjà payé, le cas échéant 0] euros et il reste dû [solde] euros.

Par la présente, je vous mets en demeure, au sens de l’article 5.231 du Code civil, de me payer la somme de [solde] euros dans un délai de [nombre] jours à compter de la réception de la présente, par virement sur le compte [IBAN] au nom de [titulaire du compte], avec la référence [référence].

[Des intérêts au taux légal sont dus sur cette somme à compter de la présente mise en demeure, conformément à l’article 5.240 du Code civil. / Conformément aux articles 5 et 6 de la loi du 2 août 2002 concernant la lutte contre le retard de paiement dans les transactions commerciales, des intérêts de retard sont dus de plein droit depuis le [lendemain de la date d’échéance], ainsi qu’une indemnité forfaitaire de 40 euros.]

Si vous estimez ne pas devoir cette somme ou l’avoir déjà payée, je vous remercie de me le faire savoir par écrit dans le même délai. À défaut de paiement dans ce délai, je me réserve le droit d’engager les procédures judiciaires appropriées.

Veuillez agréer, Madame, Monsieur, l’expression de mes salutations distinguées. [Prénom et nom ou dénomination] [Adresse]

Watch the limitation period

Most contractual claims are time-barred after 10 years (art. 2262bis of the old Civil Code, ancien Code civil), and amounts payable yearly or more often, such as rent or interest, after 5 years, as are claims for water, gas, electricity or telecom services (art. 2277). Sellers of goods to private individuals face a one-year rule (art. 2272); whether it also covers services or freelancers is unsettled. A letter you send yourself does not interrupt limitation. A court summons, a bailiff’s demand under art. 1394/21 C. jud., a seizure or the debtor’s acknowledgement, such as a part payment, does (art. 2244 and 2248). So does, once, a mise en demeure sent by your lawyer or a bailiff by registered letter with acknowledgement of receipt to a debtor domiciled in Belgium, with the statements the law lists; it opens one more year (art. 2244, § 2).

If payment still does not arrive

• Consumer debtor: after your reminder, a lawyer, bailiff or registered collection agency may send a further formal demand and must wait another 14 days; the consumer can ask for a payment plan (art. XIX.7 and XIX.9 CDE).
• Undisputed business debt: your lawyer instructs a bailiff (huissier de justice), who serves a demand to pay. The debtor has one month to pay, ask for a payment plan or dispute the debt with reasons. If it does nothing, the bailiff records the non-contestation at the earliest eight days after that month has expired, and that record becomes enforceable without a judge; the debtor can still challenge it in court within a month of service (art. 1394/20 to 1394/27 C. jud.). Both parties must be in the Belgian business register or, since 26 February 2026, in an EU business register linked to it, and interest and penalty clauses are capped at 10% of the principal.
• Injonction de payer: before the juge de paix for up to €1,860, backed by a writing from the debtor, or before the tribunal de l’entreprise (business court) between businesses, whatever the amount. It must be preceded by a demand served by a bailiff or sent by lettre recommandée avec accusé de réception (registered letter with acknowledgement of receipt), giving 15 days and reproducing art. 1338 to 1344 C. jud., on pain of nullity (art. 1339). A lawyer signs the application (art. 1340), and the debtor must live in Belgium (art. 1344).
• Ordinary claim: the juge de paix (justice of the peace) hears claims of up to €5,000 (art. 590 C. jud.); disputes between businesses go to the tribunal de l’entreprise (art. 573).

If you and the debtor live in different EU countries, the European Small Claims Procedure covers claims of up to €5,000 without a lawyer, and the European order for payment covers uncontested claims; forms are on the EU e-Justice portal. MaisonMail posts letters; it does not go to court or collect debts.

Post your letters and keep evidence

Upload your completed PDF or write your letter in MaisonMail, and add supporting PDFs in the send flow. The recipient address determines the destination; available services, estimated delivery and the final price appear before payment. A demand takes effect when it reaches the debtor (art. 1.5 C. civ.), so allow time for delivery before you count your deadline. A standard or tracked letter is valid for a reminder or a mise en demeure, but tracking shows that an item arrived, not what it contained; sending the same text by email as well gives you a dated record. MaisonMail does not send a lettre recommandée: where the law requires a registered letter with acknowledgement of receipt or a bailiff, as before an injonction de payer, use that channel, usually through your lawyer. Keep the exact letter, attachments and any delivery evidence.