Wastewater contains a wide range of biological and chemical markers related to human activity. The collection and analysis of these markers in the effluents (wastewater and sludge) allow to qualify the public health of the population and to evaluate the impact of the chemicals used in daily life on the environment. In line with these studies, the Innovation Department of SIAAP and its scientific partners (ISA and LEESU) has created an Observatory of the city with the objectives of: • Monitoring the long-term dynamics of known and/or potential pollutants according to French regulations. • Contributing to studies aimed at a better understanding of anthropogenic activities. • Structuring and centralizing data (wastewater and end-of-treatment sludge), ensuring their storage for 10 years. • Providing technical and scientific knowledge by publishing every two years the data generated by the Observatory of the city via the open platform Zenodo. Regarding the end-of-treatment sludge, the Seine Aval (SAV) plant has been chosen as a strategic location, since the catchment area corresponds to the Parisian west catchment (6.5 million inhabitants). Data on the sludge micropollution (in metals, polycyclic aromatic hydrocarbons – PAHs and polychlorinated biphenyls – PCBs) are available since 1980 and are provided in the present datasets.