In a private letter from 1963, the Situationist leader Debord first claimed that he had created this famous graffiti, but he only made this public shortly before his death in 1993.

Colored black and white photo postcard, Edition Lyna, ca. 1965. Photo and inscription [Les Conseils superflus/superfluous advice]: Louis Bouffier. Mehdi El Hajoui Collection.