A Flemish client books you, so you write the invoice in Dutch. It feels like the professional thing to do, and it is the right instinct applied to the wrong object.
Commercial courtesy belongs in the conversation. The invoice is not a conversation, it is an administrative document, and in Belgium administrative documents follow you rather than your customer.
The principle nobody explains
It follows you, not the client
A Belgian business has language obligations tied to where it is established, not to who it sells to.
A creator established in Flanders keeps Dutch paperwork whether the client sits in Namur or in Ghent. A creator established in Wallonia keeps French paperwork whether the client is in Bruges or in Liège. The client's language has no bearing on it, which is precisely the part that surprises people, because everything else in this country adapts to the person in front of you.
The question to ask once
Where exactly your obligations sit, and how Brussels works for your situation, is a fifteen minute question for your accountant or the business counter. Ask it once, at registration, and never think about it again.
What the courtesy version is for
None of this makes the polite instinct wrong. It makes it a second document.
Send the invoice as it must be, and add a plain translation of the description in the mail, or a courtesy copy clearly marked as such. The client reads what they need in their language, the file stays what it has to be, and nobody is choosing between being correct and being pleasant.
| Situation | The reflex | What actually matters |
|---|---|---|
| Flemish client, you are in Wallonia | Invoice in Dutch | Your establishment decides the document |
| Client asks for it in their language | Redo the invoice | Send a marked courtesy copy |
| Foreign client, no Belgian language | Improvise | Ask what their accounts system needs |
| You work in both languages daily | Alternate per client | One consistent document language |
The last row is the practical trap for bilingual creators. Alternating feels responsive and produces a year of invoices in two languages, which is exactly the pile you do not want to hand an accountant, and which makes your own numbering harder to follow.
What this does not change
Your quote, your messages, your delivery notes and the video itself are commercial material. Write them in whatever language wins the work.
That distinction is the whole article: be as accommodating as you like in everything that persuades, and be consistent in the thing that gets filed. Creators who mix the two end up doing extra work and looking less organised, which is the opposite of what the polite instinct was aiming for.
Keep reading
- Your hands, in an ad you never shot
- "You Said You Were Bilingual"
- The buyer nobody in your niche is emailing
- The One UGC Brief Marketing Does Not Pay For
- The complete UGC guide for Belgium
Frequently asked questions
What if a client insists on an invoice in their language?
Send the courtesy copy and keep the document as it must be. Almost nobody insists once they receive something readable, because what they actually wanted was to understand the lines.
Which language for a client outside Belgium?
Usually English, and the useful move is to ask what their supplier system expects. Foreign clients rarely care about the language, they care about the reference numbers.
Does this apply to a quote as well?
No, and that is the point worth remembering. A quote is a sales document, so write it in the language that makes the client comfortable.