Plastic pollution in oceans and rivers is of high concern because of its persistence in the environment and its potential impact on ecosystems. However, there is a specific lack of data in rivers. Here we present data from the Seine river banks in a historical polluted shore. Data were classified using international MSFD and OSPAR classifications. The sampled site is a quadrat of 1 m2 located downstream in the estuary in a visual maximum along a 1 km shore covered by plastics. A total of 20,259 plastic debris were individually counted, classified and weighted by category for a total mass higher than 4 kg. Half of the plastic debris in number are represented by preproduction pellets.