33. Every advertising sign which, originally displayed in conformity with this Act and the regulations, becomes non-conforming by reason of the construction of a new highway, a change in the site of a highway or the designation of an autoroute pursuant to section 297 of the Highway Safety Code (chapter C-24.2), must be brought into conformity with this Act and the regulations within three years after the date on which it becomes non-conforming. In a site or area described in paragraph 1 of section 17, the advertising sign must be removed within the time prescribed by the Government.