There are some interesting parallels with respect to the Charles in this Washington Post story about the ongoing clean-up of the Seine in Paris. Both rivers suffered significantly due to industrialization, urbanization and its associated pollution. The water of both has historically been perceived negatively by the local population. But the Charles and the Seine are also benefiting from major clean-up efforts including the expanded treatment of wastewater. The plan is to host swimming events in the Seine for the 2024 Olympics after which public swimming venues may open.
We’ll note one difference between the two rivers is that the Charles’ currently doesn’t host “dinghy-sized fish!”