3 How can the spouses arrange their property regime?

3.1. Which provisions can be modified by a contract and which cannot? Which matrimonial property regimes may be chosen?

The spouses have the possibility of choosing a matrimonial property regime via a marriage contract. As alternative forms of matrimonial property regime, Belgian law provides the separation of property and the universal community of property. In addition, the spouses dispose of the possibility of regulating their matrimonial property regime at their discretion, in so far as they do not stipulate anything that conflicts with public order or good morals or the default regime (Art. 1387 CC).

The separation of property regime (Art. 1466 - 1469 CC) knows only two estates: the estate of the one spouse and the estate of the other spouse. The income of each of the spouses remains separate, which means that they can each freely dispose of their earnings. Nevertheless, this does not mean that spouses who opted for separation of property cannot own anything jointly. However, the assets which they dispose of jointly are not "common", but rather "undivided". This means that the rules of the general law concerning co-ownership apply (Art. 577-2 CC). The specific status of the family home is also recognised in this regime. Spouses can opt for a separation of property, but they can also add certain clauses that ‘correct’ this separation by way of a certain form of solidarity. Additionally the spouses have to explicitly express whether they do or do not want the judicial authorities to apply an equitable adjustment in case of a divorce as a consequence of the irretrievable breakdown of marital life.

In the universal community of property regime (Art. 1453 CC) there is virtually only one common property. Regardless of how the assets were acquired, they will always belong to the two spouses jointly.

3.2. What are the formal requirements and who should I contact?

The marriage contract is a solemn contract. Marriage contracts drawn up before the solemnisation of the marriage and amendments (modification of the matrimonial regime or change to another regime) to the stipulated or statutory matrimonial property regime must be established by authentic instrument (Art. 1392 CC).

3.3. When may the contract be concluded and when does it come into effect?

A marriage contract concluded before the solemnisation of the marriage enters into effect as of the solemnisation of the marriage (Art. 1391 CC). Spouses who have not concluded a marriage contract are, as of the day of their civil marriage, subject to the statutory regime, which is one of community only of the property acquired after the marriage has begun. The spouses can, by mutual agreement, amend (modify or change) their matrimonial property regime during the marriage by authentic instrument. See 2.1 and 3.4.

3.4. May an existing contract be modified by the spouses? If so, under what conditions?

The spouses can, by mutual agreement, amend (modify or change) their matrimonial property regime during the marriage. The amendment may not be in conflict with mandatory rules of law and may not harm the interests of the family or third parties. If one of the spouses so requests, the act amending the matrimonial property regime is preceded by a notarial inventory of all movable and immovable property and of the debts of the spouses. A notarial inventory is required if the amendment of the matrimonial property regime results in the liquidation of the previous regime (Art. 1394 CC).

3.5. Can a matrimonial contract be given retroactive effect according to the national law in your country, when spouses conclude this contract during marriage?

[This information is valuable for international spouses, who have since the European Regulation (EU) 2016/1103 of 24 June 2016 went into force on 29 January 2019 have the possibility to make a choice of law with retroactive effect, see article 22 par. 3 and 4 of the regulation. It is important to know if the national law accepts the making of a matrimonial contract during marriage with retroactive effect as well, so the choice of law and the matrimonial contract can both have retroactive effect.]

A marriage contract containing a change of the matrimonial property regime is effective between the parties from the moment of conclusion of the authentic act, and towards third parties from the moment of registration in the Central Register of Marriage Contracts, see art. 1395, par. 2 Civil Code.
There is no retroactive effect of the marriage contract, nor of the changes to such a contract.
It is possible to make a choice of law with retroactive effect, see art. 50, par. 3 of the Belgian Code on Private International Law.