The glossary to understand and take action

Data minimisation

A principle consisting of limiting the personal data used to what is necessary for the intended purpose.

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

Understand the scope

Definition and points to distinguish

In an exchange with a fiduciary services firm, it leads to specifying the documents useful for each engagement and the persons who need access to them. It does not allow legally required information or supporting documents to be arbitrarily removed: necessity and obligations must be considered together.

In your file

What this changes in practice

Minimisation requires limiting personal data to what is adequate, relevant and necessary for the purpose. It applies to forms, requested documents, access and exports. Collecting more just in case is not sufficient justification. It is also necessary to distinguish what must be retained for an obligation from what may be deleted or should not be requested.

A scenario to help you understand

Educational example

An initial professional contact form asks for useful contact details and a description of the need, without requiring a copy of an identity document at this stage.

Fictitious situation, presented to illustrate the concept.

Prepare for what comes next

Points to check

  • Justifier chaque donnée demandée
  • Limiter les accès
  • Définir des durées adaptées

The practical question

Find out more

La minimisation signifie-t-elle supprimer tous les justificatifs rapidement ?

Non. Certaines pièces doivent être conservées pour une obligation ou une finalité justifiée. Il faut distinguer les données nécessaires de celles qui ne le sont pas et définir des durées adaptées. Une politique de conservation doit aussi limiter les accès et prévoir la fin de conservation, au lieu d’opposer stockage illimité et suppression immédiate.

Connecting concepts

Terms to know as well

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

GDPR — protection of personal dataThe General Data Protection Regulation governs the processing of personal data within its scope of application.Processor within the meaning of the GDPRThe processor processes personal data on behalf of a controller, within the framework of the applicable instructions and conditions.KYC — know your customerKYC covers customer due diligence procedures used in particular as part of anti-money laundering due diligence obligations.Anti-money laundering — AML/CFTAnti-money laundering and counter-terrorist financing requires the professionals concerned to comply with due diligence, organisational and cooperation obligations.National identification number — 13-digit identification numberThe national identification number of a natural person in Luxembourg comprises 13 digits and enables identification in the relevant procedures.MyGuichet.lu professional spaceA collaborative space enabling a company, self-employed person or association to manage certain administrative procedures and information.

Put it into practice

Explore further with our guides

Practical guidePersonal data and fiduciary services: governing document exchanges

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.