The glossary to understand and take action

Accounting document

An accounting document is a document that substantiates a transaction: an invoice, statement, contract or other evidence appropriate to its nature.

Notion comptable, fiscale ou juridique · Luxembourg Fiduciaries Editorial Team · Reviewed on

Understand the scope

Definition and points to distinguish

Proof of payment does not always describe the service provided. Keep references that make it possible to link the document, entry, approval and payment.

In your file

What this changes in practice

An accounting document must make it possible to understand the nature of the transaction, the parties, the date and the amount. Depending on the case, an invoice must be supplemented by a contract, a delivery note or a business justification. A bank statement proves a movement, but rarely its full substance. Durable filing, reference-based searches and the management of corrections facilitate checks and transmission to the accounting firm.

A scenario to help you understand

Educational example

A card payment appears on the bank statement. The company also keeps the invoice and the business purpose of the expense to enable its filing and review of its tax treatment.

Fictitious situation, presented to illustrate the concept.

Prepare for what comes next

Points to check

  • Conserver le document original ou sa version conforme
  • Relier pièce, opération et paiement
  • Protéger les archives et leurs accès

The practical question

Find out more

Un paiement bancaire peut-il remplacer la facture ?

Le paiement prouve un mouvement de fonds, mais ne renseigne pas nécessairement le bien ou service acheté, les parties et le traitement TVA. Conservez le justificatif adapté à l’opération et son lien avec le règlement. Si une pièce manque, cherchez à l’obtenir auprès de son émetteur plutôt que de considérer le relevé comme une réponse universelle.

Connecting concepts

Terms to know as well

Continue with the concepts, contacts and procedures related to this topic.

Audit trailA set of links and records making it possible to understand a transaction from its source document through to its recording and controls.Purchase invoiceA purchase invoice describes the goods or services invoiced to the company by a supplier.Expense claimStatement through which a person submits business expenses incurred and the supporting documents required for their processing.AccountantThe accountant records and monitors transactions, reconciles supporting documents and prepares financial information within the scope of their duties.BookkeepingBookkeeping consists of recording transactions, filing their supporting documents and monitoring accounts according to a regular organisation.General ledgerThe general ledger presents the movements recorded in each accounting account, together with their references and amounts.

Put it into practice

Explore further with our guides

Practical guideBusiness expenses: checking their deductibility in LuxembourgPractical guideDigitising accounting: documents, automation and human oversightPractical guideAccounting documents: organising filing and retentionPractical guideBank reconciliation: understanding and handling discrepancies

Sources and verification

References consulted on 20 September 2026. Official procedures specify the applicable conditions and exceptions.

This guide explains a general process. The applicable rules depend on your situation; it does not constitute personalised advice. Report a correction.

A definition gives you a reference point. To examine your situation, clarify your question with a professional.