The fliers warn men not to hand over their bank cards to sex workers or to give them details about their pin, reports the Hamburger Abendblatt.
It advises only paying in cash and taking only as much cash as needed to pay for the service.
Police say that prostitutes try and persuade customers to pay via card, offering them a smartphone which allegedly carries out the transaction when they enter their pin into it..
But the prostitutes then store and reuse the pin number to take money from their client’s account, usually withdrawing the daily limit. In most cases this lies between €1,000 and €3,000, but it can sometimes by a five-digit number.
“Many Hamburgers know this trick already,” a police spokesperson said. But tourists are the ones particularly vulnerable to it, he said, saying that a good amount of common sense often wasn’t enough.
“Some of the women are exceedingly cunning,” the spokesperson said.
Hamburg police say that the number of reports of such tricks had fallen in 2015 as a whole, but December saw a sharp rise.
Police also assume that the actual number of such cases is higher than reported.
“Many people are afraid to receive post at their house and therefore don’t make a complaint,” said the spokesperson.
Police add, though, that the majority of prostitutes working in Hamburg’s red light district are law-abiding.
“We are trying to target areas about which we have had a particular number of complaints,” said the spokesperson.