The event, held beside Museum Island in the city’s Mitte district, was organised by Fluss Bad Berlin, a group campaigning to reintroduce public swimming to the German capital after a ban that’s lasted nearly 100 years.
The protest was officially registered, sidestepping the swimming ban, which was introduced in 1925 due to pollution.
Campaigners say the river is now clean enough on most days and point to Paris, where the Seine has recently reopened to swimmers.
