A more thorough explanation:

Definition: Clameur de haro is a French term used in the Channel Islands to protest against trespass to land. It is a legal remnant from when the Duchy of Normandy held the islands before England took control in the 13th century. The victim's cry of haro (repeated 3 times) is popularly supposed to be an abbreviation of Ha Rollo, the first Duke of Normandy. The full cry, Haro, Haro, Haro, a l'aide, mon prince, on me fait tort, when registered at the local records office, enjoins the offender from possessing the land.

Example: If someone is building a fence on your land without your permission, you can use the clameur de haro to protest against it. You would shout "Haro, Haro, Haro, a l'aide, mon prince, on me fait tort" to stop the person from possessing your land.

Explanation: The example illustrates how the clameur de haro can be used as a legal tool to protect one's land from trespassers. By shouting the cry, the offender is warned that they are committing a wrongful act and must stop immediately. This tradition has been passed down for centuries and is still recognized in the Channel Islands today.