On 1 July 2024, the register for working partners and assistants was introduced in the Belgian construction and cleaning sectors. As part of the broader fight against social security fraud, businesses in these sectors are required to list their working partners and assistants in this register using a specific application in the Crossroads Bank for Enterprises (CBE). This will help ensure fair competition and the efficient collection of social security contributions. In addition, a further withholding obligation will be introduced in 2026.
A working partner is a natural person who owns at least one share in a company and is active in Belgium within the company without an employment contract.
An assistant is a natural person who helps or stands in for a self-employed person in the exercise of his/her profession, also without an employment contract.
Directors of companies and self-employed persons in the cleaning and construction sectors must register their working partners and assistants via My Enterprise | Belgium.be. They can log in using an eID, Itsme or a mobile app. If necessary, a natural person can be authorised to perform the registration for the company or the self-employed person.
This registration requirement is completely separate from affiliation with a social insurance fund, where this is mandatory.
An exemption from the registration obligation applies to:
The national register number or BIS number of the working partner or assistant must be included in the register, as well as the start date and, where applicable, the end date of the activities as a working partner or assistant.
A BIS number is a unique identification number in Belgium for persons who are not registered in the National Register but who do have dealings with the Belgian government.
Feel free to contact us if your working partner or assistant does not yet have a BIS number. We will be happy to assist you with applying for one.
Registration must take place before the activities concerned begin. If the working partner or assistant was already working before 1 July, the registration must take place no later than 31 December 2024. When the activities cease, this must be recorded in the register within 15 days.
The National Institute for the Social Security of the Self-Employed (NISSE) will carry out checks on these registrations. In the event of non-registration or incomplete registration, the company or self-employed person may be fined €500 to €4,000 per infringement.
From 2026, the withholding obligation for the cleaning and construction sectors will be extended. In addition to tax and social security debts for personnel, clients must check whether the contractor or subcontractor has other outstanding social security contributions.
For an outstanding debt of more than €2,500, you as the client will have to forward 15% of the invoice amount (excl. VAT) to NISSE.
You should therefore always check the website Check inhoudingsplicht before making a payment and keep on record proof that you have done so.
Private clients do not need to monitor the withholding obligation.
For the time being, this withholding obligation only applies to the cleaning and construction sectors, with possible extensions in the future.
If you have any further questions, your regular advisor at Grant Thornton will be happy to provide expert advice and practical assistance.