"Non-natives who desire to found commercial or agricultural establishments in the districts above Stanley Pool, or in others to be eventually designated by the Governor-General of the Congo, shall be at liberty to take possession with this view of an area, the maximum size of which shall be fixed by the Governor-General; provided that they fulfil such conditions as he shall lay down, they shall enjoy a preferential right to the eventual acquisition of property in such lands at a price which shall be fixed by him beforehand."