Under normal circumstances, the Seine divides Paris in half. In recent weeks, however, geographical demarcations have been less pronounced than garbological ones. Alongside workers in numerous other sectors, the city’s trash collectors are participating in a nationwide strike to protest an unpopular reform that will raise France’s standard retirement age by two years. As of last week, nearly ten thousand tons of garbage sat uncollected on the streets—but only in half of the city. This is because waste is collected by public workers in the Second, Fifth, Sixth, Eighth, Ninth, Twelfth, Fourteenth, Sixteenth, Seventeenth, and Twentieth Arrondissements, while private companies manage the refuse of the First, Third, Fourth, Seventh, Tenth, Eleventh, Thirteenth, Fifteenth, Eighteenth, and Nineteenth. As Delphine Bürkli, the mayor of the Ninth, explained in an e-mail to her…