pelouse interdite

Pelouse Interdite”: There must be a story behind this photo in the café Le Faubourg in Paris, France. It looks like it’s from the 1930s. Is it a protest against the “keep off the grass” sign? Or are these people simply ignoring it, the way Parisians are wont to do? In the 12 years since Socialist Bertrand Delanoë became mayor, by the way, most “pelouse interdite” signs have disappeared.