Last updated on 13 February 2023
Why is it necessary to declare foreign income in the Luxemburgish tax return?
Even if the foreign income is not taxable in Luxembourg, it is incorporated into a fictitious tax base to determine the overall tax rate applicable to Luxembourg taxable income.
French income
You will need your December salary slip (cumul de l'année).
Belgian income
You will need your "Compte individuel" certificate or the salary slip for the tax year.
German income
You will need your "Lohnsteuerbescheinigung" certificate.
