E-invoicing Luxembourg: public sector obligations

Who must issue an electronic invoice in Luxembourg?

Any economic operator invoicing a Luxembourg public sector body under a public contract or concession contract must issue a structured electronic invoice. The obligation does not depend on company size: it has covered all operators since 18 March 2023.

The decisive condition is not the client's status but the nature of the contract. Legislation treats as a public contract any written contract between an economic operator and a public sector body covering works, supplies or services.

The applicable framework is the law of 13 December 2021 amending the law of 16 May 2019, in force since 18 December 2021, together with the grand-ducal regulation of the same date designating the common delivery network.

What is the legal timetable?

The obligation rolled out in three phases, counted from the entry into force of the law. No remaining phase is outstanding today.

Is a PDF enough to invoice a public administration?

No. The format required by law is XML, or a file containing XML. A PDF invoice, however legible and however complete its VAT particulars, does not satisfy the obligation. Central administrations no longer accept PDF invoices.

The legislator's reasoning is functional. A PDF invoice requires re-keying or fallible automated reading at the recipient's end, whereas a structured invoice feeds directly into the accounting system.

How does the Peppol network operate in Luxembourg?

The grand-ducal regulation of 13 December 2021 designates Peppol as the common delivery network for automated receipt of electronic invoices by public bodies. The network is managed by OpenPeppol, an international non-profit association under Belgian law.

The duty does not sit with the sender alone. Economic operators issue compliant invoices. Public sector bodies use Peppol for receipt and, until they operate their own access point, that of the State Information Technology Centre. Ministries and State administrations use the CTIE access point.

The sender does not connect directly to the network. It goes through a certified access point, operated by a provider or built into its accounting software. The model is a four-corner network: sender, sender access point, receiver access point, receiver.

What happens if the invoice is not compliant?

The immediate consequence is not a fine but an operational one: the invoice is not processed. The document is rejected or left unanswered, which delays collection.

On a public contract with long payment cycles, the cash flow effect is the real cost. A rejection at quarter end pushes collection back by a full payment cycle, with no recourse against the administration since the sender is at fault.

The watch point applies to receipt as well as issuance. A company selling to the public sector also buys, and its own suppliers are progressively moving to the structured format.