Guerrilla gardening is becoming of age - after the UK and Canada, it is now hitting Paris. Guerrilla gardening is political gardening, a form of non-violent direct action practiced by environmentalists. Wikipedia has a definition here. Try the blog www.guerrillagardening.org as a resource for illicit acts of cultivation in a war against neglect of public space. Or a softer version of urban adventure and growing food on www.primalseeds.org/guerilla.htm. Well it is a form of protest, and although it is probably illegal from a land rights perspective, it is way better than tags. I for one hope it catches on!