Tax number

Steps

1. Declare your arrival and register at the commune (sheet LU-SEJOUR-TOUS-001). The data you declare there feeds the RNPP, which assigns you your number; if you do not receive it, ask for an extract of your RNPP data at your commune's counter (or consult it on MyGuichet.lu with a LuxTrust certificate).
2. If you are an employee: your employer declares you to the Centre commun de la sécurité sociale (CCSS) within 8 days of your entry into service. You then automatically receive your social security card.
3. Your tax withholding card is issued automatically by the Administration des contributions directes (ACD) after your affiliation to the CCSS, in 30 working days on average. Your employer receives an electronic version.
4. If you do not receive your card within 30 working days of your first day of work, contact the competent RTS office (income tax withholding on salaries and wages) and inform your employer.
5. If you do not live in Luxembourg, are not Luxembourgish and do not yet have a number, you can request it online on MyGuichet.lu, without authentication, but only for one of the professional reasons that Guichet.lu lists: registration of a pleasure boat under the Luxembourg flag, transmission of payment information in the fight against tax fraud, filing of salary or pension account statements, application for or modification of an establishment authorisation, aid to an SME or a new business.

Documents

• For registration at the commune: those in sheet LU-SEJOUR-TOUS-001.
• For a request for professional purposes (non-resident): copy of your valid identity document (identity card or passport) electronically signed with your LuxTrust certificate or another qualified electronic signature, certificate of residence less than 6 months old and proof of the professional reason.

Costs and timelines

• Cost: free (the request for professional purposes is free, according to guichet.lu).
• Format: 13 digits ("13-digit matricule" on Guichet.lu; Official Journal of the EU, 2016/C 481/08).
• Timelines: declaration to the CCSS by the employer within 8 days; tax withholding card in 30 working days on average; for a request for professional purposes, extract sent by post within 2 weeks of the update of the data.

Common pitfalls

• Starting to work without a tax withholding card. Chase the RTS office if it does not arrive within 30 working days.
• Changing address without telling the commune. Your tax card is updated from this change: an omission can distort your withholding.
• Asking the RNPP for the number by email. To protect your data, the RNPP is not authorised to communicate the number electronically or to pass it on to third parties (rule stated for the request for professional purposes, whose extract is sent by ordinary post).
• Wanting the number for a company. It is assigned to a natural person, not to a business.

What changes by country of origin

• EU and EEA citizens: number assigned through registration at the commune.
• Swiss nationals: same procedures as EU citizens.
• British nationals (Scots included): same logic once in regular residence as a third-country national or as a beneficiary of the withdrawal agreement (sheet LU-SEJOUR-TOUS-001).