Boateng escaped with only minor injuries after the attack, which reportedly took place in Kaarst on Christmas Day.
“On Wednesday, 25.12.2013, at around 12:45, an incident of physical assault took place in Kaarst. A 26-year-old man, a resident of Meerbusch, was physically attacked on the street by a currently unidentified man," a police statement said.
"There are indications that the motive for the crime is connected to the personal affairs of the 26-year-old. The man was mildly injured. Criminal investigators have begun their work."
According to German newspaper Bild, Boateng was leaving the house of his ex-wife after visiting his son on Christmas Day when he was struck by the assailant and fell on a vase. The 26-year-old later checked into a local hospital with bruised ribs, back and neck, the paper added.