Decorative outdoor works, trompe l'oeil on exterior walls

Its purpose is to stay bright every night. Under Mr Sarkozy's five-year term, it had been discussed to shut down the cities at 10.30 p.m. as a cost-saving measure. This "test" sign would have remained visible without electrical energy. The powerful urban lighting in the surrounding area does not reveal this function, but it is present.

Chilly-Mazarin in Essonne.