Filing an electronic income tax return for natural persons using MyGuichet.lu

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Resident and non-resident taxpayers who are subject to taxation (taxation by assessment) in Luxembourg are required to report their income by filing an income tax return (form 100). If there is no tax liability, resident and non-resident taxpayers can, upon request, file a tax return (form 100) in order to be taxed by assessment.

Since the 2021 tax year, eligible taxpayers can file their personal income tax return online via an electronic assistant on the MyGuichet.lu platform if they receive the following:

  • profit from the exercise of a liberal profession (available since the tax year 2022);
  • income from a salaried occupation;
  • a pension or annuities; or
  • rental income.

Taxpayers who do not fall within the scope of this electronic procedure can file their tax return by sending the PDF file of their tax return via MyGuichet.lu or by post.

Who is concerned?

Taxpayers concerned

All resident or non-resident persons:

  • subject to a tax return obligation (following a request from the Luxembourg Inland Revenue - ACD) or who wish to file a tax return upon request; and
  • who receive income in Luxembourg from:
    • a liberal profession; and/or
    • a salaried occupation; and/or
    • pensions or annuities; and/or
    • from the rental of property, including interest on a loan taken out to finance their main residence.

These individuals must not have:

  • been married more than once during the tax year;
  • changed country of residence during the tax year;
  • a separate country of residence from their spouse in case of joint taxation.

Since 2022, partners in a civil partnership can use the electronic procedure to apply for joint taxation or after having applied for it previously they can file a joint income tax return.

Types of income to be reported

Only income received from salaried employment, a liberal profession, a pension/annuity or the rental of goods can be declared electronically.

This procedure does not apply to anyone with the following types of income:

  • commercial profit;
  • agricultural and forestry profits;
  • net investment income;
  • miscellaneous net income;
  • extraordinary income, in particular income from the sale and/or cessation of the practice of a liberal profession.

Special expenses in relation with a liberal profession can also be declared using the electronic procedure.

Exclusion from the electronic procedure

In the context of an electronic tax return, taxpayers can request but not revoke:

  • joint taxation by assimilation of the non-resident to the resident.

Note: if the withholding tax forms of a non-resident couple show a tax rate, then this couple can use the electronic procedure because the assimilation mode has already been requested in advance as the rate has been entered on the withholding tax form.

Furthermore, the taxpayer cannot use this version of the electronic procedure to request or after having previously requested:

  • joint taxation upon joint request between a resident taxpayer and a non-resident person, who do not live de facto separated, provided that the resident taxpayer earns at least 90 % of the household's professional income during the year in Luxembourg;
  • purely individual taxation or taxation with reallocation of adjusted joint taxable income.

In addition, the current version of the procedure does not allow taxpayers to apply for:

  • an annual adjustment;
  • a tax reduction for children in the form of tax relief, or a tax allowance for children.

With regard to extraordinary expenses, only the flat-rate deductions for disability and infirmity, domestic service costs, assistance and care expenses, as well as tax allowances for children who did not belong to the household can be claimed through the electronic procedure.

Prerequisites

The person submitting and signing the income tax return (i.e. the declarant) needs:

  • a LuxTrust product or a Luxembourg electronic identity card (eID); and
  • a national identification number (13-digit social security number).

Preliminary steps

Those who wishes to file a tax return electronically must have an eSpace on MyGuichet.lu, more particularly:

  • either a private eSpace if the declarant is the taxpayer concerned or if they are a private proxy (e.g. their parents, etc.);
  • or a business eSpace if the declarant is the taxpayer's authorised representative (e.g. a fiduciary, a lawyer, etc.).

Note: if the tax return is submitted by a representative, the latter must have a power of attorney from the taxpayer (form 101) and attach it to the procedure as a supporting document. This power of attorney is not required if the representative is a lawyer.

Anyone who does not yet have an eSpace on MyGuichet.lu can consult our help pages to find out how to create a private and/or business eSpace.

Deadlines

The personal income tax return must be submitted by 31 December of the year following the tax year in question at the latest, while respecting the specific deadlines of the letters received from the various ACD departments.

Example: for tax year N, the tax return is due by 31 December of year N+1.

Anyone who requires an extension of the deadline for submitting the tax return should apply for the extension (preferably by fax or post) to the competent tax office.

In the event of failure to meet the indicated deadlines, an additional tax, a late payment fee or a penalty may be levied by the tax office.

Taxpayers who refuse to file their tax return will force the tax office to determine the tax liability using the estimated assessment procedure (taxation d'office par voie d'estimation).

How to proceed

Filing an application

Taxpayers or their representatives (e.g. a fiduciary), must submit the income tax return for natural persons electronically through their private or business eSpace on the MyGuichet.lu platform.

In order to easily complete the tax return, the entry of data can be initiated by submitting an XML file on MyGuichet.lu.

The person submitting and signing the income tax return (i.e. the declarant) needs:

  • a LuxTrust product; or
  • an Luxembourg electronic identity card (eID).

After initiating the process, the declarant is invited to follow the instructions provided by the assistant in order to complete the declaration.

Electronic signature

The income tax return submitted via MyGuichet.lu requires a signature with an authentication and electronic signature certificate contained in:

  • a LuxTrust product; or
  • a Luxembourg electronic identity card (eID).

The electronic signature cannot be performed with an eIDAS means of identification from another country.

Specificities in the event of joint taxation

If the income tax return is not submitted by a representative, both taxpayers must sign the tax return electronically in case of joint taxation.

If one of the taxpayers does not have their own certificate, it is possible to use the other taxpayer's certificate for both signatures. To do so, the taxpayer must declare that he/she is the representative of his/her spouse or partner (option available since the 2022 tax year) under 'Indications générales - Mandataire contribuable conjoint/partenaire' (not available in English) when using the electronic assistant.

This possibility does not exist for the 2021 tax year. Thus, the name and surname of the taxpayer who signs the declaration twice with their certificate must be stated in the field 'Désignation du mandataire' (Designation of the representative).

In both cases, the certificate holder must also:

  • fill in a power of attorney agreement (available for download under 'Forms / Online services') for their spouse or partner; and
  • add it as a mandatory attachment to the tax return.

If it is not explicitly stated that the taxpayer is the representative of their spouse or partner, signing with the same certificate twice is not allowed and therefore each taxpayer must use their own certificate.

Supporting documents

Taxpayers can attach supporting documents to the electronic income tax return.

Note: depending on the declarant's situation, certain documents must be attached to the tax return.

For example, if the declaration is submitted by a representative, the latter must attach the form granting them the power to file the tax return.

Obligations

The taxpayer(s) must:

  • declare the income of all persons who are jointly taxable (all amounts must be declared in EUR);
  • give their consent to the exclusively automated processing of the electronic income tax return. The taxpayer may withdraw their consent at any time.

Withdrawal of consent can be made by letter to the competent tax office until the tax has been accounted for.

In the case of joint taxation, the withdrawal of consent by one of the spouses is sufficient to ensure that taxation cannot be carried out exclusively by automated means.

A taxpayer who does not wish to give their consent to exclusively automated processing can file their income tax return using the form 100, which can be downloaded from the ACD's website and submitted:

Tutorials

Online services and forms

Who to contact

Luxembourg Inland Revenue

Related procedures and links

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