The evidence of the past is very negative regarding the cleanliness of streets and squares in pre-industrial cities. However, the authorities in charge of urban policing were very concerned about the cleanliness of the streets. Police regulations forbade dumping garbage, imposed street sweeping and organized the removal of sludge and debris. The gap between the implementation of these measures of cleanliness and the image of urban dirt can be explained by the nature of the negative discourse emanating from supporters of reforms and from elites whose perception of urban waste became different during the eighteenth century.