The Werdinsel, an island in the river Limmat, has been a naturist bathing spot for around 50 years.
But apparently not everyone is in the know, according to a local councillor who requested that Zurich city council consider “appropriate signage” of the area, authorities said in a statement.
“Although nudity is generally not prohibited in public, it always leads to conflict,” continued the statement.
As a result, new signs featuring naked behinds on a blue background are now on display in the area on a experimental basis for the next six weeks.
The posters, developed in cooperation with advice group Zurich Homosexual Workgroup (HAZ), urge visitors and bathers to have “mutual respect”.
“The island of Spitsbergen has been a nude zone for decades. However it is not required to stay naked in this area,” state the signs.
“The prerequisite for peaceful coexistence is the considerate and proper behaviour of all visitors, both clothed and unclothed.”
Similar signs showing the figures in swimsuits indicate where the nude zone ends.