"It was a real annoyance that was growing and growing," St Pauli Interest Community (IG St Pauli) board member and owner of several local bars Uwe Christiansen told The Local. "We wanted to bring people to reason."

While researching ways to discourage “Wildpinkler” – “free pee-ers” – annoyed members of IG St Pauli came across a hydrophobic paint which literally makes water droplets bounce off.

That means that anyone hoping to relieve themselves in unorthodox locations around the neighbourhood must reckon with the risk of a soaking for their shoes and trousers.

Now there are signs reading “Don't pee here! We'll pee back,” on specially-treated walls around the area.

"I've seen in Facebook and the local newspapers that the reactions were very positive. People were just tired of the peeing on walls, home entrances and playgrounds," Christiansen said.

The group recommends that partygoers take extra care, as not all the walls they've painted are marked with signs.

“Watch out! From now on, it's Peeback time,” said Julia Staron of IG St Pauli in the group's video.