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The sign says it all: Residents in St Pauli, the party district of Hamburg, have had enough of drunken people - 'revellers' in media parlance - urinating in the street.
In order to combat wildpinkler ("free pee-ers"), water-repellent paint more commonly found on ships has been used on buildings in the red-light district of Reeperbahn.
Julia Staron, spokesman for the IG St Pauli group, said the neighbourhood now "pees back".
"On the streets here, it's like being in a sewer," she told Der Spiegel.
"The liquid rebounds with almost the same force with which it hits."
So, revellers in St Pauli beware, for in a video produced by the group that you can watch below, Ms Staron, with a broad grin on her face, added: "Not every wall has a sign."
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