They dress up in pink catsuits, have names like "Spider Mum" and feel a social obligation to plunder the most expensive restaurants and gourmet delicatessens in town as part of a campaign to help the poor.
Last week the well-heeled citizens of Hamburg's Altona district got a taste of their antics when 30 of them marched into the city's luxury "Fresh Paradise Goedeken" supermarket and walked out five minutes later with €15,000 (£10,000) worth of stolen goods.
The gang's booty included magnums of Champagne at €99 a bottle, filets of Japanese Kobe beef at €108 a kilogram, legs of venison, a salmon and several boxes of Valrhona chocolate.
Before leaving, gang members thrust a bouquet of flowers into the hands of a shop assistant. Attached was a handwritten note which proclaimed: "Survival in the city of millionaires would be impossible without us!" It was signed by "Spider Mum", "Santa Guevara" and "Multiflex".
Another note later released by the gang insisted that the haul had been distributed to Hamburg's needy, to the "social workers, cleaning ladies and minimum-wage earners". It added: "The places of wealth in this town are as numerous as the opportunities to take it."
"It was a well-planned robbery," Carsten Sievers, the store's manager, said on Friday last week. "Somebody had obviously been in the shop before the main contingent arrived and had already filled up several shopping trolleys."
Fourteen squad cars and a police helicopter scoured the Altona district for more than an hour after the robbery, but failed to find the perpetrators.
"The gang covered its tracks completely. They act like professionals," Bodo Franz, the head of a Hamburg police unit investigating the robbery, said.
As they left the scene of the robbery, the gang, clad in masks, catsuits, dark glasses and rubber masks, posed for a group photo outside the supermarket and brandished their booty in front of the camera.
The incident was the latest attack perpetrated by this Robin Hood-style gang of so-called "Spontis", whose activities have alarmed and baffledthe Hamburg police and the city's well-to-do. Yet the gang, which refers to itself as "Hamburg for Free", does not strike often. Its last attack took place almost exactly a year ago, when 40 masked men and women stormed the Süllberg restaurant in the city's wealthy Blankenese district overlooking the river Elbe.
Diners were appalled as the gang snatched titbits from the plates in front of them and started stuffing the stolen food into their mouths. Other gang members brandished a huge knife and fork made out of silver foil and cardboard above the diners' heads. A placard declaring "The fat years are over" was strung between pillars in the restaurant.
Mr Franz, who has been trying to track down the "Hamburg for Free" gang since the incident a year ago, said that investigators had merely established that the group was probably made up of a mixture of students and anarchists.
"We don't know much about them. They are very political yet one of their main motives is fun," he said. "The problem is that they strike so rarely and so professionally that they are a major job to catch."Reuse content