In the early years of the French Revolution, the red flag was a sign of martial law, displayed by the gendarmerie to warn civilians that if they didn't disperse they would be fired on. But in July 1792 the Jacobin journalist Jean-Louis Carra printed on the flag, in black letters, 'Martial Law of the Sovereign People Against Rebellion by the Executive Power', thus making the red flag the flag of revolution.¹

Since that moment, and for most of the nineteenth and twentieth centuries, the colour red has symbolised the fight against oppression and the pursuit of a social organisation based on equality. Today, however, after the fall of the Berlin Wall, red is again seen as a sign of warning, in contrast to the colour green understood as that of nature, of openness, of the originary and the authentic - and perhaps, too, of the market. What perhaps is the colour's key note - disruption - still remains, but what is being disrupted has changed: if originally it symbolized an end to disorder (that of the revolutionary masses) and later an end to a certain order (of the State, or of capitalism), today it is again used, at least in the West, to warn against disorders (of illegal immigrants, of terror attacks and non-Western values) which threaten the social and productive relations of late capitalism.

This story of changes in the meaning of a sign, of its appropriation and subsequent loss by a certain position, is key to understanding how individuals organise (or disorganise) their life in common. Both social structures and political struggles can be partially accounted for by means of such