You obviously haven't looked up the rules to see what kind of permit the poles are given.

All 'road marking' stakes have a 'Saisonnier' Permit which only allows them to stay a maximum of nine months (heaven forbid that we should need them for so long), after which they are sent home. They can renew their permit in autumn for the next season.

Could one of the Mods please move these posts to the 'Permits' Forum. Some old stick-in-the-mud might need the information sometime.