Can a landlord in the private sector increase rent with retroactive effect without prior notice?

Questioner

Is the landlord allowed to implement rent increases retroactively without notice in the private sector? Received an email today stating that a rent increase must be paid retroactively for 6 months. Is that allowed?

Lawyer

In the Dutch legal system, a landlord in the private sector is in principle free to determine the rent himself. However, it is not allowed to increase the rent without any announcement, nor to do so retroactively. A rental agreement must at least include the initial rent. The rental agreement may include a provision stating that the rent will be increased annually. When and by how much the rent may be increased must be specified in detail in the contract. In general, the increase must be announced in a written notice to the tenant. Also, a reasonable period of notice must be given prior to the rent increase, usually at least one month. If a landlord wants to increase the rent in an unfair or incorrect way, the tenant can object and possibly ask for help from a legal advisor. Depending on the circumstances, the tenant may also be able to go to the rent assessment committee or the court.