E-invoicing in Luxembourg: PDF, XML, Peppol and MyGuichet.lu explained

A PDF is not an electronic invoice

This is the most common misunderstanding: a “digital” invoice is not necessarily an electronic invoice in the legal sense.

The amended law of 16 May 2019 on electronic invoicing in public procurement and concession contracts defines an electronic invoice as an invoice issued, transmitted and received in a structured electronic form that allows its automatic and electronic processing. As the Chambre des Métiers puts it, that means an XML file, or a file that contains XML, and not simply a PDF, a Word document or another unstructured format.

What an invoice must contain does not change: the mandatory details are the same. To review them one by one, see our article on the 10 mandatory invoice details.

Who is concerned, and since when?

According to Guichet.lu, the obligation covers every economic operator that sends an invoice or a credit note to a contracting authority or contracting entity under a public contract or a concession contract. It has applied to all economic operators since 18 March 2023, whatever their size. A credit note is treated as an invoice and follows the same rules.

The reference texts are Directive 2014/55/EU of 16 April 2014, the amended law of 16 May 2019 and the Grand-Ducal regulation of 13 December 2021. Public bodies, for their part, must receive electronic invoices through the Peppol network.

The format: XML and the European standard EN 16931

The file must follow the most recent version of the European standard on electronic invoicing (EN 16931) and one of the syntaxes on the list published by the European Commission. Guichet.lu mentions Peppol BIS Billing 3.0 (UBL) and XRechnung (UBL or UN/CEFACT CII).

• The XML file is the one that is legally binding; the human-readable copy that comes with it is only a summary.
• Attachments can complete the invoice, in PDF format only.
• From 1 October 2026, XRechnung versions older than 3.0 are no longer accepted.

In practice you do not write this XML yourself: your invoicing software or your Peppol service provider generates it from the invoice data.

The two authorised channels: Peppol or MyGuichet.lu

Guichet.lu is explicit: transmission channels other than Peppol or MyGuichet.lu are not authorised, and email is not allowed.

Example: invoicing a ministry, step by step

A fictitious company, Atelier Lumen SARL, renovates an office for a ministry. This is a public contract, so its invoice must be electronic.

1. 1
   The software creates invoice 2026-042: EUR 12,400.00 excluding VAT, VAT at the standard rate of 17% of EUR 2,108.00, so EUR 14,508.00 including VAT.
2. 2
   It generates the XML file that follows the European standard, with the same structured data: number, date, supplier, buyer, amounts.
3. 3
   The file travels on the Peppol network (or, without a connection, through a MyGuichet.lu form), never by email.
4. 4
   The administration receives the file and processes it automatically, without re-keying.

Names and amounts are illustrative. To check a VAT calculation, use our Luxembourg VAT calculator.

What about invoices between businesses? The EU timeline

Today, the Luxembourg obligation described above covers invoices sent to public buyers. The European framework is moving: the VAT in the Digital Age (ViDA) package was adopted on 11 March 2025 and is being rolled out progressively until January 2035.

In other words, structured invoices will also become the norm for sales between businesses in two EU countries. Starting now with complete, properly numbered invoices makes the transition easier.

Checklist before invoicing the State

• Is your client a contracting authority (ministry, administration…) under a public contract or a concession? Then an electronic invoice is mandatory.
• Are the mandatory details complete? They are the same as on paper.
• Is the file an XML that follows the European standard (for example Peppol BIS Billing 3.0)?
• Are you using Peppol or MyGuichet.lu, not email?
• Do you have the purchase order at hand if you use the form without authentication?

For an overview of the tax, read our Luxembourg VAT guide and explore Zuelen’s features.