Personal income tax

Sole proprietorships and partnerships are not directly liable for income tax.

The tax is payable by:

  • the entrepreneur in the case of a sole proprietorship;
  • the partners in the case of a partnership.

The tax applicable (personal income tax or corporate income tax) depends on the status of the partner concerned.

Who is concerned

Taxable persons can be grouped into 2 categories:

  • the entrepreneur in a sole proprietorship, i.e. the natural person exercising a commercial activity in his/her own name. Only the entrepreneur has a legal personality and a personality for tax purposes. The owner who is taxed on any income, with the income from the sole proprietorship being only one component of this income;
  • the partners in transparent partnerships (SENC, SCS, de facto companies, or civil companies) which are subject to a regime comparable to that of sole traders, namely:

Foreign service providers

Generally speaking, profit from the occasional provision of services is not subject to income tax in Luxembourg.

Nonetheless, if the business has a permanent establishment from a tax standpoint (depending on the tax treaty applicable), profit generated from these services is taxable in Luxembourg.

Example: profit from a Belgian business carrying out construction work in Luxembourg is taxable in Luxembourg if the duration of the work exceeds 6 months.


In order to be taxable, profit from a sole proprietorship or partnership must be derived:

  • from commercial or craft activities;
  • from agricultural or forestry activities;
  • or from exercising a liberal profession.

Commercial or craft activities

An activity is considered as commercial from a tax standpoint if it meets the following four criteria:

  • it is independent (which excludes salaried activity);
  • it is for profit (which excludes amateur or unpaid activities);
  • it is permanent (which excludes isolated acts);
  • and it constitutes a participation in general economic life (it must target a large market).
Examples: a shoe repairer, a decorating business, or a taxi company.

Where the profit from a partnership does not meet these 4 criteria, it is nonetheless considered commercial profit if one or more of the majority partners are:

Partners of this type of partnership must therefore also declare the profits derived from this company as commercial profit.


  • a civil company (partnership) exercises a commercial activity (within the meaning of the above definition): its partners are liable for tax on the profit they receive from the company as it is derived from a commercial activity;
  • natural persons are partners in a limited partnership (société en commandite simple) exercising a non-commercial activity. As the activity is not commercial, the partners are not taxed on its profit;
  • a public limited company (société anonyme - SA) holding 70% of a civil real estate company which does not perform any commercial activity. As the majority shareholder is a capital company (SA), the profit is considered as commercial. All the partners in a civil company are therefore liable for tax on the profit that they receive from it.

Agricultural or forestry activities

Activities considered as agricultural or forestry from a tax standpoint specifically include:

  • agriculture, forestry, viticulture, horticulture, fruit and vegetable growing, in nurseries or greenhouses;
  • livestock farming;
  • bee-keeping;
  • hunting and fishing conducted in conjunction with farming or forestry.

Profit derived from these activities must therefore be declared as profit from agricultural and forestry activities.

Exercising a liberal profession

Activities considered to be liberal professions from a tax standpoint specifically include the following, if they are exercised as independent activities:

  • scientific, artistic, literary, teaching or educational activities;
  • doctors, dentists, veterinary surgeons, midwives, physiotherapists, masseurs;
  • lawyers, notaries, bailiffs, executors of wills, property managers, accountants and tax advisers;
  • engineers, architects, chemists, inventors, consultants, journalists, photo-journalists, interpreters and translators, etc.;
  • directors, auditors of SA, SARL, SECA, cooperative companies (sociétés coopératives - SC), etc.

Profit derived from these activities must therefore be declared as profit derived from exercising a liberal profession.

How to proceed

Sole trader/Partner natural person

Natural persons must declare profit derived from a sole proprietorship or partnership on their personal income tax return (form 100F):

  • in the commercial profit category if it results from a commercial or craft activity within the meaning of tax law.
    In such cases, the tax return must be accompanied by the declaration for the calculation of commercial profit and business tax (110F);
  • or in the agricultural or forestry profit category;
  • or in the profit derived from the exercise of a liberal profession category;

Any business losses may be deducted:

  • from the owner's total income in the case of a sole proprietorship;
  • from each partner's income pro rata according to his/her share of the partnership.

In the event of insufficient income, the residual loss can be carried forward by the taxpayer indefinitely against future income.

Carrying losses forward is subject to the following two conditions:

  • carrying out proper bookkeeping for the financial year during which the loss occurred;
  • the carrying forward of losses is limited to losses which have not been offset by other net income or a restatement of net profits.

Partners in capital companies

Capital companies must declare profit derived from a partnership on their corporate income tax return.

Forms / Online services

Déclaration pour l'impôt sur le revenu 2020 pour personnes physiques résidentes et non résidentes (modèle 100)

Les informations qui vous concernent recueillies sur ce formulaire font l’objet d’un traitement par l’administration concernée afin de mener à bien votre demande.

Ces informations sont conservées pour la durée nécessaire par l’administration à la réalisation de la finalité du traitement

Les destinataires de vos données sont les administrations compétentes dans le cadre du traitement de votre demande. Veuillez-vous adresser à l’administration concernée par votre demande pour connaître les destinataires des données figurant sur ce formulaire. Conformément au règlement (UE) 2016/679 relatif à la protection des personnes physiques à l'égard du traitement des données à caractère personnel et à la libre circulation de ces données, vous bénéficiez d’un droit d’accès, de rectification et le cas échéant d’effacement des informations vous concernant. Vous disposez également du droit de retirer votre consentement à tout moment.

En outre et excepté le cas où le traitement de vos données présente un caractère obligatoire, vous pouvez, pour des motifs légitimes, vous y opposer.

Si vous souhaitez exercer ces droits et/ou obtenir communication de vos informations, veuillez-vous adresser à l’administration concernée suivant les coordonnées indiquées dans le formulaire. Vous avez également la possibilité d’introduire une réclamation auprès de la Commission nationale pour la protection des données ayant son siège à 15, boulevard du Jazz L-4370 Belvaux.

En poursuivant votre démarche, vous acceptez que vos données personnelles soient traitées dans le cadre de votre demande.

Einkommensteuererklärung 2020 für ansässige und nicht ansässige Personen (Vordruck 100)

Ihre in diesem Formular erfassten personenbezogenen Informationen werden von der zuständigen Verwaltungsbehörde verarbeitet, um Ihren Antrag erfolgreich abzuschließen.

Diese Informationen werden von der Behörde für den zur Verarbeitung erforderlichen Zeitraum gespeichert.

Die Empfänger Ihrer Daten sind die im Rahmen Ihres Antrags zuständigen Verwaltungsbehörden. Um die Empfänger der in diesem Formular erfassten Daten zu erfahren, wenden Sie sich bitte an die für Ihren Antrag zuständige Behörde.

Gemäß der Verordnung (EU) 2016/679 zum Schutz natürlicher Personen bei der Verarbeitung personenbezogener Daten und zum freien Datenverkehr haben Sie das Recht auf Zugang, Berichtigung und gegebenenfalls Löschung Ihrer personenbezogenen Informationen. Sie haben zudem das Recht, Ihre erteilte Einwilligung jederzeit zu widerrufen.

Weiterhin können Sie, außer in Fällen, in denen die Verarbeitung Ihrer Daten verpflichtend ist, Widerspruch einlegen, wenn dieser rechtmäßig begründet ist.

Wenn Sie diese Rechte ausüben und/oder Einsicht in Ihre Informationen nehmen möchten, können Sie sich unter den im Formular angegebenen Kontaktdaten an die zuständige Verwaltungsbehörde wenden. Sie haben außerdem die Möglichkeit, bei der Nationalen Kommission für den Datenschutz Beschwerde einzulegen (Commission nationale pour la protection des données, 15, boulevard du Jazz L-4370 Belvaux).

Wenn Sie Ihren Vorgang fortsetzen, akzeptieren Sie damit, dass Ihre personenbezogenen Daten im Rahmen Ihres Antrags verarbeitet werden.

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