Living together in Belgium: what are the legal implications of your status?

PUBLISHED ON 25/02/2026

Co-habiting in Brussels as expats raises a number of key legal questions. The implications differ between a de facto relationship, legal cohabitation and marriage, in terms of taxation, estate, inheritance and welfare. In Brussels, in particular, these choices may have a tangible impact on your expat situation. The Expat Welcome Desk will guide you through the key differences to support you in making an informed choice.

De facto relationship (de facto cohabitation)

A de facto relationship exists when two people live together without making an official declaration to the municipal administration.

Principal characteristics:

No formality required to establish it
Assets and income are completely separate
Limited legal protection in the event of separation
No legal duty of assistance (except for private agreements regarding common costs)
No automatic inheritance right
No survivor’s pension
No liability for the partner’s taxes

It is essentially the simplest status, but also the one with the least legal protections.

Legal cohabitation

Legal cohabitation concerns two people – a couple but not necessarily (friends, members of the same family, co-living) – who live together and register their status by means of an official declaration to the municipality. This declaration creates a recognised legal status, without modifying the civil status as would be the case in marriage.

Conditions:

Both parties must be of full legal age and possess full legal capacity
The parties cannot be married nor committed in another legal cohabitation
They must be domiciled at the same address in Belgium
They must be present in person to sign the declaration

How does it work in practice?

Both partners appear together before the civil registrar for their municipality
A declaration is signed by both parties
Registration in the Belgian National Register gives rise to reciprocal rights and obligations

Main rights and obligations:

Official registration
Joint taxation (one tax return per household)
Protection of the family home: if one partner alone owns the property, they cannot sell, lease or mortgage the family home without the agreement of the other party
Obligation to contribute to the household expenses commensurate with respective income
Limited inheritance rights. In the event of death intestate (without a will), the surviving partner enjoys the usufruct on the family home and its contents (moveable property), however these rights may be removed in a will
No right to a survivor’s pension unlike in marriage
Legal cohabitation comes to an end through marriage, death or by means of a written declaration (jointly or unilaterally) to the municipality. Compared to marriage, it is relatively straightforward to dissolve.

This status offers a moderate level of protection, while remaining more flexible than marriage.

Marriage

Marriage ceremonies are officiated within the municipality and create a complete legal relationship between the spouses. Unlike legal cohabitation, it changes your civil status.

Conditions:

Both future spouses must be of full legal age and possess full legal capacity
The parties cannot be married already, nor committed in another legal cohabitation
No obligation to live together before the ceremony
Marriage is prohibited between close family members (parents, children, brother, sister)

How does it work in practice?

Marriage declaration and file at the municipality
Official ceremony before the registrar
Registration in the Belgian National Register

Principal characteristics:

Extensive reciprocal rights and obligations
Joint taxation (one tax return per household)
Protection of the family home (authorisation of the other spouse required for the sale or mortgaging of the home)
Legal duty of assistance
Automatic inheritance rights (unless otherwise stipulated in a contract or will)
Enhanced financial protection
Choice of a system of matrimonial property (community of property, separation of property, etc.)
Formal procedure required in the event of divorce

Marriage entails more extensive protections and obligations than legal cohabitation, notably from a property perspective.

The impact on expats in Brussels

For expats, the choice of status may impact:

International estate planning
Tax and joint taxation
Rights with regard to social security/welfare
Pension rights
Protection in the event of separation or death

How Belgian law and the law of your country of origin are reconciled may have significant consequences. Tailored legal advice is therefore highly recommended.

Who should you consult in case of need?

A notary (notaire/notaris) is a key point of contact for any matters relating to your family and estate situation.

• The website of the Fédération Royale du Notariat belge [Royal Federation of Belgian Notaries] details all notaries in Brussels and the languages they speak: https://www.notaire.be
• The initial consultation at a notary is free of charge
• You are free to choose your notary

The notary will be able to check your status in the Belgian National Register, advise you on the most suitable status and assist you in drafting a marriage contract, cohabitation agreement or will.