The work to defuse the British bomb meant that buildings within a 1.5-kilometer radius had to be evacuated. That meant getting people out of two hospitals, several homes for the elderly, the university and parts of the historic old town, German Press Agency (DPA) reported.
Patients in two further hospitals had to be moved to more secure parts of those facilities. More than 1,000 volunteers helped fire crews, police and emergency services make sure that all residents were clear of the danger zone by noon (1000 GMT).
Emergency shelters were also set up.
The bomb was discovered a week and a half ago during construction work in a garden. It was buried only 80 centimeters deep, meaning it could cause significant destruction if it goes off.