The bomb will be defused following the evacuation on Sunday, the press release said.
Authorities claimed that they found the unexploded World War Two bomb on Tuesday.
Almost 70,000 people will be evacuated over the weekend in Frankfurt after an unexploded World War 2 bomb was found on Wednesday.
A police spokesperson said on Wednesday that 70,000 people will likely have to leave their homes, meaning that nearly one in ten of the city's 717,000 inhabitants will be affected.
Two hospitals fall within the evacuation zone, and patients there will be temporarily taken to other hospitals, city officials said.
The bomb is an HC 4000 air mine, nicknamed "Wohnbockknacker", for its capability to wipe out an entire street.
It was found on Wismarer Strasse, which is close to the city centre and 2.5km (1.5 miles) north of the main shopping area in the city.
The evacuation will begin at 8:00 a.m. on Sunday, with the bomb disposal happening later that day and taking about four hours. There is no danger at present and the bomb site is cordoned off by police.
It is not unusual for unexploded bombs from WWII to be found during construction work in German cities. A similar evacuation took place last Christmas when another British bomb was discovered in an unexploded state, requiring the evacuation of 54,000 people.
The 1,400kg device - codenamed "Cookie" by the RAF - was dropped by a British wartime bomber sometime after 1941.