The footage shows Svetoslav S, with beer bottle in hand, approach the unsuspecting woman from behind, before kicking her in the back, sending her flying forward. The victim suffered a broken arm and wound to the head.
During his trial, the 28-year-old Bulgarian had admitted kicking the woman down the stairs but had not remembered anything until police released the CCTV footage.
On the night of the attack he had taken a cocktail of drugs: alcohol, marijuana, cocaine and crystal meth, Süddeutsche Zeitung reports.
The wife of Svetoslav S told the court he had been aggressive and dependent on recreational drugs since a car crash in 2008