WARNING: This page is about a different car, the 2005 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Removing Front License Plate Bracket To Bumper Bolts
Courtesy of GENERAL MOTORS CORP.
Remove the bolts that retain the front license plate bracket to the bumper.
Remove the front license plate bracket from the bumper.