A cadastral income notification is challenged with the FPS Finance; a Walloon property tax (précompte immobilier) assessment notice with SPW Finances. These procedures do not replace each other. Identify the document you have received and its own deadline: waiting for one administration's reply does not protect your right to challenge the other.
Which document have you received?
Cadastral income, or CI, is determined by the federal administration and serves as the basis for calculating property tax. The assessment notice, often called an AER in French, demands the tax assessed by the Walloon administration. The SPW Finances FAQ (in French) explains why the two administrations must be distinguished.
Note the property concerned, the amount, the references and the dates on each letter. To understand the nature of the figure before discussing its amount, read our guide to cadastral income.
How do you object to a new cadastral income?
According to the FPS Finance procedure (in French), notification of a new CI opens a two-month period. For an objection to be valid, the FPS requires:
- a counterproposal stating the CI you consider appropriate for the property;
- a registered letter sent no later than the deadline stated in the notification;
- submission to the competent office, whose address appears in that notification.
The FPS specifies that if the deadline falls on a Sunday or public holiday, it is moved to the next working day. Start from the document received rather than an approximate calculation. A telephone request or ordinary email does not replace the registered letter. Simply writing that the amount seems excessive does not provide the required numerical counterproposal.
How do you challenge Walloon property tax?
The official Walloon procedure (in French), updated on 19/10/2026, states that the objection must reach the administration within six months of the date on which notification of the assessment notice takes effect. This date appears on the letter. The objection must give grounds: clearly explain the reasons for your disagreement.
The official form can be completed online. The paper version must be completed and signed, then submitted in accordance with the administration's instructions. Keep proof of submission and receipt. The payment deadline and the objection deadline are two different reference points: the former is not used to calculate the latter.
Are you challenging the CI and receiving a property tax assessment based on it? The SPW FAQ cited above requires two separate objections. Do not wait for exchanges with the FPS to end before examining the assessment notice and its own deadline.
Which documents should you prepare without complicating the file?
Our method is to separate the two procedures and keep a simple index of the documents:
- the CI notification and the evidence allowing its notification to be traced;
- the complete assessment notice, its references, the date on which notification takes effect and the payment deadline;
- your precise request, including the numerical counterproposal for the CI;
- supporting documents linked to the grounds raised, followed by copies of the steps taken and replies received.
This filing system is a preparation method, not an additional legal requirement. Proof of submission to the FPS does not prove that SPW Finances has received an objection. Before a sale in the Province of Liège, also keep decisions with the house documents: distinguish the assessed amount, the disputed amount and a correction actually granted.
What are the answers to frequently asked questions?
Must you pay property tax while challenging it?
Yes. The official Walloon procedure specifies that an objection does not suspend the obligation to pay by the date shown on the assessment notice. A favourable decision may result in a credit note and a refund of the overpayment. If payment is difficult, contact SPW Finances to discuss your situation rather than assuming that the deadline has been suspended.
Does buying a house allow you to challenge an old CI?
No. The FPS specifies that buying a property does not reopen the right to object to a previously determined CI. Its page describes exceptional possibilities for reassessment, particularly for a proven material error or certain new and permanent external circumstances. These have their own conditions and do not simply extend the original deadline. Have the grounds and documents examined before choosing this route.
Does a property tax reduction follow the same procedure?
Not necessarily. Wallonia distinguishes applications for reductions, particularly for a modest home, family dependants or disability, from applications for proportional relief. It refers applicants to the specific forms. Identify your grounds first, without assuming that a general objection replaces the appropriate form.
What if the disagreement over CI persists?
The FPS describes a process of negotiation, followed by tax conciliation if no agreement is reached. Arbitration may follow and incurs costs. Before that stage, ask for the calculation and cost allocation rules applicable to your file; if you consult an adviser, have their remit and cost clarified. This cadastral process must not automatically be applied to Walloon property tax.
Are you also preparing a sale? Request your valuation report to place your house in its market context. Handling the tax dispute remains a matter for the administration and your competent adviser.
