What is a property sale mandate?

A property sale mandate is the written contract by which an owner instructs a real estate agent to market and negotiate the sale of a property. In Belgium it must be in writing, set a duration and a commission, and follow the consumer rules of the Royal Decree of 28 September 2023 (in force 1 February 2024).

The mandate (mandat de vente) is the legal foundation of the relationship between a seller and an agency. Without it, an agent cannot lawfully advertise your home, receive offers on your behalf or claim a commission. It is a consumer contract, so the law frames it tightly.

Belgian rules require the mandate to be written and to state the essentials: the property, the asking price, the agency’s tasks, the commission and how it is calculated, and the duration. Since the Royal Decree of 28 September 2023, applicable from 1 February 2024, one set of protections applies whether the contract is signed at the office or elsewhere. A consumer who signs benefits from a 14 calendar-day right of withdrawal (IPI, 2024).

There are two main forms. A simple (non-exclusive) mandate lets you appoint several agencies and sell yourself. An exclusive mandate reserves the sale to one agency, usually in exchange for stronger marketing and a single point of contact. Notice periods are capped by the same decree: a maximum of two months for an open-ended contract, and one month for a fixed term of three months or less renewed tacitly (IPI, 2024).

A point owners rarely expect: the agency’s commission can be due even after the mandate ends if a buyer the agency introduced later completes the purchase. Reading the presentation clause matters as much as the price.

At a glance