From The Times this week: (via my mum)

Motorists in the Paris area faced chaos after two feuding districts re-routed road markings to leave two one-way streets facing each other. Authorities in the suburb of Levallois-Perret decided that the D909 route brought too much congestion into the area, and made it a one-way street, forcing traffic into neighbouring Clichy. However, Clichy retaliated by declaring its section of the D909 also one-way, but in the opposite direction.