Invoice Requirements for Self-Employed in Luxembourg

An invoice (facture / Rechnung) in Luxembourg has to include a specific list of mentions to be legally valid. Get them wrong and your business client may refuse to pay, your VAT deduction may be rejected at audit, or the AED can fine you. The good news: most rules are common sense, and not every "mandatory mention" applies to every self-employed person.

The rules come from four laws stacked together: the VAT law (Loi du 12 février 1979, as amended), the RCS law of 19 December 2002, the company law of 10 August 1915, and the establishment law of 2 September 2011. Guichet LU consolidates all of them into one practical checklist.

Mandatory Mentions for Standard Invoices (over 100 EUR TTC)

A standard invoice has to include three groups of information: who you are, what the invoice is, and what the transaction is.

About you (the issuer):

• Your name or trade name (raison sociale / Firmenname) and legal form
• Your registered address (siège social / Geschäftssitz)
• Your VAT number (numéro de TVA / Umsatzsteuer-Identifikationsnummer)
• Your RCS number — if you're registered (more on this below)
• Your business permit number (numéro d'autorisation d'établissement) — if you hold one

About the invoice itself:

• Issue date
• A unique sequential number
• Date of supply or service completion (if different from the issue date)

About the transaction:

• Customer's full name and address
• Customer's VAT number — only if applicable (intra-EU B2B, mostly)
• Quantity and nature of goods or services
• Unit price excluding VAT
• Discounts or rebates
• Taxable amount, broken down per VAT rate
• The VAT rate(s) applied
• The VAT amount due
• Total including VAT

What Goes on Your Invoice Depends on Your Legal Form

This is where most confusion happens. The same "mandatory mention" rules are not actually the same for everyone.

A few important details:

• The "profession" line is required only for sole-trader artisans and merchants. A plumber who works as a sole trader writes "Plombier — Aut. n° 10123456/0". A consultant working as a sole trader doesn't have to write a profession line.
• The RCS number is required only if you're actually registered in the RCS (Registre de commerce et des sociétés / Handelsregister). Sociétés are always registered. Sole-trader commerçants are required to register; artisans usually qualify as commerçants in practice and end up registered too. Liberal-profession sole traders are not required to register — and therefore they don't put an RCS line. See our full guide on RCS registration for self-employed.
• Cooperatives are explicitly excluded from the RCS-on-invoices rule by law.
• The business permit number is required if you hold one. Most commercial, craft, industrial, and regulated liberal activities need a permit. Many liberal professions (IT consulting, copywriting, translation, design, etc.) don't.

Simplified Invoices for Small Amounts (100 EUR TTC or Less)

If the total invoice amount including VAT is 100 EUR or less, the law allows a much shorter list:

• Issue date
• Your name and address
• The quantity and nature of the goods or services
• Total price including VAT
• The VAT amount, or enough information to calculate it

Special Mentions When They Apply

Some situations require an extra line on the invoice. The most common ones for self-employed people in Luxembourg:

For B2C invoices (selling to consumers), there's a useful — but conditional — mention to know about. If you want to preserve your right to claim legal late-payment interest from a consumer who pays late, you have to: (1) issue the invoice within one month of the supply, and (2) expressly state on the invoice that you intend to claim legal late-payment interest if payment is late. Without that sentence, you cannot claim interest later. It's optional in the sense that nothing forces you to add it — but if you skip it, you've waived your right to interest. For B2B transactions, late-payment interest applies automatically by law, no mention needed.

For more on cross-border situations, see our article on the EU SME VAT franchise. For verifying your business client's VAT number before invoicing, see our guide on how to check a VAT number on VIES.

"Do I Need to Show the VAT Rate on Each Line?"

This is one of the most common questions — and the strict legal answer is no, not literally on each line.

The VAT law requires:

• The taxable amount broken down per VAT rate, and
• The VAT rate(s) applied and corresponding VAT amount(s).

That means:

• If your invoice has only one VAT rate (typical: 17% for most services and goods), one summary block at the bottom is enough.
• If your invoice mixes rates (e.g. 3% on books and 17% on consulting in the same invoice), you must group amounts by rate in the summary.

In practice, the simplest and clearest layout is to put the rate next to each line. That's what every Luxembourg accounting tool does, and what every accountant expects. It is not legally required line-by-line, but it is the safest format — especially if your invoice mixes rates.

"Do I Need My Customer's RCS or VAT Number?"

The customer's RCS number is never required by Luxembourg law. Only the customer's full name and address is mandatory.

The customer's VAT number is required only in specific cases:

• Always when you sell to a business in another EU country (B2B intra-EU)
• Strongly recommended when you sell to a Luxembourg business — gives them legal certainty that your invoice is deductible
• Not required when you sell to a private consumer

For a business client, the safest practice is: ask once, save the VAT number with the customer record, verify it on VIES, and put it on every invoice you send them.

Numbering and Timing

Numbering:

• Sequential — no gaps in the series
• Unique — every invoice number can appear only once
• You can use multiple series (e.g. "INV-2026-001", "EU-2026-001") as long as each is internally sequential

Timing — when to issue the invoice:

• By the 15th of the month following the supply or service completion. So if you finish a job on 18 March, the invoice has to be issued no later than 15 April.
• For continuous services (subscriptions, retainers), the rule applies to each billing period.

Modifying an Invoice = Issuing a New Invoice

A rule that surprises a lot of people: any document that modifies an invoice in a specific and unequivocal way is itself a new invoice, in the eyes of Luxembourg law.

That has two consequences:

1. You cannot just delete an invoice once it's issued. The correct way to cancel or correct is a credit note (avoir / Gutschrift), which is itself a "new invoice" with all the mandatory mentions.
2. An email saying "please ignore line 2 of invoice 2026-014, the price was wrong" is legally a new invoice — and therefore must carry a unique number, your full identity block, the modified amount, the VAT impact, etc.

In practice: if you need to change something, issue a proper credit note. We have a full guide on how to cancel or correct an invoice.

Paper Invoices, PDF Invoices, Electronic Invoices

The legal content rules are the same regardless of the channel — paper, PDF, or electronic file. What changes is the format and how it's transmitted.

Today (2026):

• B2G (selling to public-sector buyers in Luxembourg): electronic invoicing is mandatory through the Peppol network, via the official portal at efact.public.lu (Ministry of Digitalisation).
• B2B and B2C: electronic invoicing is optional. Paper or PDF invoices remain fully legal.

Coming up:

• Luxembourg is expected to introduce legislation on mandatory domestic B2B electronic invoicing, with a likely go-live in the 2028–2029 window. As of May 2026, no draft law has been formally published.
• The EU has set a deadline of July 2030 for cross-border B2B invoicing to be electronic across all member states.

What Happens If Your Invoice Is Incomplete

Three real consequences, in increasing order of seriousness:

1. Your customer's bookkeeper rejects the invoice. This is by far the most common — and the most painful. Larger companies, in particular, will refuse to pay an invoice that's missing mandatory mentions until you reissue it. This costs you days or weeks of cash flow.
2. Your customer cannot deduct the VAT. The AED can deny input VAT recovery on a non-compliant invoice. A customer who notices this in advance will refuse the invoice; one who notices it after a tax audit will come back and ask you to reissue, often months later.
3. AED fines and audit findings. Repeated or systematic non-compliance can trigger tax fines under the VAT law. For severe cases — like operating without a business permit while invoicing — the establishment law foresees criminal sanctions.

In day-to-day practice, the first two consequences are what drive compliance. The third is rare for an individual self-employed person, but real.

Quick Reference Checklist

Use this list before sending any invoice:

Trust is earned invoice by invoice. Bravo for earning it every single time.
🙌💜 Your BravoLisa Team

This article is for general information purposes only and does not constitute professional tax, legal, or accounting advice. Every situation is different — consult a qualified professional (tax adviser, accountant, or lawyer) for advice specific to your circumstances. BravoLisa does not accept liability for decisions made based on this information.

Last updated: May 2026. Rules and thresholds may change — always verify with the relevant authorities for the most current information.

Sources verified on 2026-05-02: Guichet LU — Facture, Loi du 2 septembre 2011 — droit d'établissement, Loi du 19 décembre 2002 — RCS, eFact — Luxembourg B2G e-invoicing portal.

Updated on: 04/05/2026