The group feels that giant billboards are excessive and a form of visual harassment; an affront to their aesthetic rights. With TV and radio, they argue, you have a choice about participating, but out in the world, you have no choice but to see the advertising. France has a long history of strikes and rebellion and so it's no surprise that these rallies are done in the light of day on the fourth friday of every month. They spraypaint billboards while the police wait patiently to arrest each person as they finish.
The group's ultimate goal is to see the scale of advertising reduced to posters no larger than 50x70 cm and in place of the huge panneaus would like to see the space dedicated to art and community life. Such measures would "lead to the resting of the eye and mind."
For a message so deeply about aesthetics and personal well being, though, it is a bit ironic that their defacement of the giant billboards isn't a little bit more, well, pretty. They might take a tip from Brazil.
Top image: deboulonneurs.org, Final Image: Tony de Marco