Between five and six young people assaulted a 45-year-old homeless man at the Hansaplatz station in western Berlin on Sunday, punching him in the face.
The perpetrators also robbed the man of his cigarettes, drinks and two sleeping bags, a police spokesman said.
The victim suffered a broken nose and was hospitalized after the assault. Medical officials contacted police.
Just over a week ago, the country was shocked when four teenagers severely beat a house painter at Berlin's Lichtenberg metro station.
The 30-year-old remains in critical condition after the brutal attack, while his teen assailants have been arrested. They could face charges of attempted murder and causing grievous bodily harm.
Investigators initially lamented the inaction of some witnesses, who failed to intervene in the attack. But days later reports emerged that a member of the Bandidos motorcycle gang had likely prevented the boys from beating up the painter's co-worker by flashing a weapon at them.