We are all submerged by useless adverting.

A simple action would be to put a sticker with the words "STOP ADS" on your mailbox.
Like WeeDoo, 5% of the french population would have already put this sticker on their mailboxes.

WeeDoo's suggestion:
Look in the Municipal Corporations for the sticker "STOP ADS" or make one yourself on a sticker : pdf for printing.