Is it permissible to impose financial charges on merchants in general weekly markets under the pretext of purchasing the rights to these markets from the state?

If the claim of ownership of the usufruct of these courtyards is valid, then it is permissible to demand compensation from the merchants who display their goods there. This is a sale of usufruct, which is permissible in Islamic law. The validity of the claim can be verified by referring to the official authorities.