An unknown assailant planted a home-made bomb on Thursday evening under a car that belongs to a Giza traffic officer who was organising traffic in the busy Hossary Square in the 6 of October city, a ministry of interior spokesperson said.
The officer sustained minor injuries and was transferred to a nearby hospital.
Earlier in the evening, Ahram Arabic news website had reported that a bomb-laden vehicle exploded in the 6 October City outside Cairo.
Egypt has been hit by a series of deadly bombings, mainly targeting security forces, since the ouster of Islamist president Mohamed Morsi in July of last year.
The attacks were initially focused on the restive Sinai Peninsula before spreading into strategic Nile Delta cities and the capital.
Last week, three explosions outside Cairo University killed a senior police official and injured five others.