Breathalysers no longer required in French law - some misunderstanding about the sponsor of the law being shareholder in the only two French breathalyser manufacturers.
Just returned from French trip - used the Halford jobbies, and promptly removed them on my return home using liquid lighter fluid (as used for Zippo lighters etc) £1.05 from Waitrose. Hold a cloth below them on the lens, put on a little lighter fluid and catch excess in cloth, peel off with your finger nail. Polish off as required. Apparently, the longer you leave them the harder they adhere.
My MK2.5 was also harder to remove from than my MK3.5