6 Nothing in this Agreement shall be construed as preventing a Party from imposing on the earnings of a company attributable to a permanent establishment in that Party, or the earnings attributable to the alienation of immovable property situated in that Party by a company carrying on a trade in immovable property, a tax in addition to the tax that would be chargeable on the earnings of a company that is a resident of a Party. Any additional tax so imposed shall not exceed five per cent of the amount of those earnings that have not been subjected to such additional tax in previous taxation years. For the purpose of this provision, the term “earnings” means the earnings attributable to the alienation of such immovable property situated in a Party as may be taxed by that Party under the provisions of Article 6 (Income from Immovable Property) or of paragraph 1 of Article 13 (Capital Gains), and the profits, including any gains, attributable to a permanent establishment in a Party in a year and previous years, after deducting therefrom all taxes, other than the additional tax referred to herein, imposed on those profits in that Party.