Patents
If the patent is simply licensed, personal property tax is deducted at the source by the Belgian debtor at the time of paying the royalty for the licence.
If the patent is not conceded, but operated by a foreign enterprise direct, the profits from its use are treated as professional income and are liable to professional tax on the basis of an annual declaration by the recipient of such income.
Professional tax is applied to subsequent profits from the sale or surrender of a patent when the recipient of the income is domiciled for fiscal purposes in Belgium. The principle of this, however, has been questioned and jurisprudence has not given a definite ruling on the matter.