By 1850, the population of Paris had grown to one million inhabitants and the city still had no more than a few dozen kilometres of sewers. In the context of a cholera pandemic, sewage wound up either in cesspits that were seldom waterproof, or worse still, directly in the Seine… While building the modern Paris on the surface, the city authorities undertook an extensive sanitation plan and gradually adopted the principle of universal connection to the sewage network. It became compulsory for privately-owned buildings to
