The great conundrum of French history is the French Revolution, or rather, the sequence of revolutions, coups and insurrections during which the nation was repeatedly destroyed and recreated. How is it that a heap of cobblestones, furniture and overturned vehicles — handcarts in 1848, 2CVs in 1968 — erected at particular points on the Left Bank of Paris can bring down a régime whose domain extends from the North Sea to the Mediterranean? As Baudelaire observed when Napoleon’s nephew conducted a coup d’état in 1851 and installed himself as supreme leader, it seemed that ‘absolutely anybody, simply by seizing control...