What is the difference between a formal notice and a dunning letter?

A dunning letter is a friendly reminder with no formal legal standing. A formal notice, by contrast, is a legal act that sets a binding deadline and triggers specific legal effects, such as late-payment interest running or the right to take court action. It must explicitly use the words "formal notice" and be sent via an enforceable channel, such as bpost registered mail with return receipt.

How long a deadline must you give in a formal notice in Belgium?

Belgian law sets no universal deadline: it depends on the context. For a commercial debt between businesses (B2B), 7 to 14 days is common practice. For an individual (B2C) or in a lease dispute, 15 to 30 days is more typical. In practice, a deadline that is too short may be deemed unreasonable by the judge, which would weaken your case.

Is a formal notice mandatory before going to court in Belgium?

In most Belgian contractual disputes, a formal notice is not an absolute condition of admissibility, but it is strongly recommended and sometimes required by law (for example for commercial late payments). Without it, the judge may refuse certain interest or indemnity claims and may also penalise the lack of an amicable attempt.

Can an email replace a registered letter for a formal notice?

Generally not, unless the parties have expressly agreed by contract that electronic communication constitutes notification. An ordinary email does not provide enforceable proof of reception. Paper bpost registered mail with return receipt or a qualified eRegistered remain the safest channels, as they provide legal proof of sending and presentation to the recipient.

Can you send a formal notice by eRegistered (eBox) in Belgium?

Yes. The qualified eRegistered has the same legal value as a paper registered letter under Belgian law. It works best when the recipient has activated their professional eBox or consented to this notification method. For an individual whose eBox is inactive, paper registered mail remains the safest channel. Bjet24 supports both paper and eRegistered sending from the same platform.

Formal Notice Belgium: free template & procedure 2026

What a formal notice is for

A formal notice (mise en demeure / ingebrekestelling) is the letter by which a creditor (or more broadly, any party who considers their rights infringed) summons the other party to perform an obligation within a specified deadline, failing which precise consequences will be drawn.

Under Belgian law it has three key functions:

it sets a date from which, for example, late-payment interest on an unpaid invoice starts running,
it constitutes a mandatory prerequisite in several procedures (amicable-settlement law, B2B collection, etc.),
it proves the creditor's good faith: they attempted to resolve the dispute before going to court.

A poorly drafted formal notice — or one sent by simple email — can be challenged and cost you weeks at the time of proceedings. For unpaid invoices, consider sending a formal dunning letter first; see our guide on unpaid-invoice dunning letters in Belgium before escalating to a formal notice.

The mandatory mentions

To be fully enforceable, your formal notice must contain:

the precise identification of sender and recipient (company name, CBE/VAT, address),
the nature of the obligation not complied with (invoice number, contract clause, etc.),
the exact amount claimed (principal, any interest, costs),
the deadline granted to perform (often 8, 14 or 30 days depending on context),
the explicit mention "formal notice",
the date and signature of the sender or their authorised representative.

For a B2B debt, the Belgian law on late payments imposes a specific deadline and form when you wish to trigger the legal interest and the flat-rate collection indemnity.

Ready-to-adapt template letter

[Sender company name]
[Address]
[CBE / VAT]

[Recipient company name]
[Address]

At [Place], on [date]

Subject: Formal notice — invoice no. [xxx] dated [date]
Sent by registered mail with return receipt

Dear Sir or Madam,

Save error or omission on our part, your account with our
company currently shows an unpaid balance of [amount] €,
corresponding to invoice no. [xxx] due since [date].

Despite our previous reminders, we have not received this
amount. By this letter, we formally put you on notice to
proceed with the payment of this sum within a period of
[14 calendar days] from receipt of this letter.

Failing payment within this deadline, we reserve the right
to claim late-payment interest at the legal rate together
with a flat-rate collection indemnity, and to entrust
collection to a third party or to the courts, the whole at
your expense.

Yours faithfully,

[Name and position of signatory]
[Signature]

Adapt the deadlines and wording to your situation (B2C, B2B, lease, employment contract…). If in doubt, have it reviewed by a lawyer.

Which sending channel: paper or electronic?

For a formal notice to be useful, proof of reception is essential. Two options:

Paper bpost registered with return receipt: the standard. You get an enforceable proof of posting and delivery. The preferred channel when facing an individual or when you are not certain the recipient uses their eBox. Our complete guide to registered mail with bpost in Belgium covers the full posting and tracking process.
Qualified eRegistered: legally equivalent, cheaper, instant. Particularly suited between companies who have activated their eBox or contractually accepted the electronic channel. Read our comparison of eRegistered vs paper registered mail in Belgium to choose the right option.

In both cases, keep the proof. It is the proof that opens the deadline.

The procedure step by step

Draft the letter following the template above, personalising the factual elements.
Verify the address: for a company, the registered office as listed in the CBE/BCE; for an individual, the official domicile.
Choose the channel: paper registered or eRegistered, depending on the recipient.
Send and immediately keep the proof of posting.
Note the date from which the deadline runs (reception or presentation, depending).
Wait for the deadline to expire before any further action (amicable collection, summons, etc.).

Three classic pitfalls

Sending the formal notice by simple email. Without enforceable proof of sending and reception, it can be challenged.
Addressing a branch instead of the head office. A company is notified at its registered office as listed in the CBE/BCE.
Forgetting to wait for the deadline to expire. An action started before the deadline expires can be declared premature.

Automating formal notices with Bjet24

For a collections team, the hidden cost of a formal notice is not the stamp — it is the time. With Bjet24 you generate the letter from a template, inject the customer/invoice data, and the sending goes out as bpost registered or eRegistered. Proofs of posting and delivery are automatically archived in the customer file. Check our online registered-mail pricing — from €2.63 per letter, VAT and postage included.

Summary

An effective formal notice combines three ingredients: legally complete content, an enforceable channel and a preserved trace. Master the three, and you will win most disputes before even needing a lawyer.