A spokesperson from power company Stromnetz Hamburg explained that cables in the ground had been damaged during construction work.
The blackout began at about 12.30pm, according to regional broadcaster NDR. This hit ice cream shops and restaurants particularly hard during the heat of the day as they had to throw out their goods due to a lack of functioning appliances.
Car shops also had to halt some services as they could not use their hydraulic lifts.
The underground U1 line was also hit by the power outage.
After more than eight hours, all affected households were lit up again by about 9pm on Tuesday, according to the power company.
Stromnetz Hamburg told NDR that the incident was “an absolutely exception” to the norm.