Do you still need to buy a Chicago city sticker if car is registered at your old address in the suburbs and have that sticker?

No, you do not need to buy a Chicago city sticker if your car is registered at your old address in the suburbs and you have that sticker. The Chicago city sticker is only required for vehicles that are registered within the city of Chicago. If your car is registered in the suburbs, you will need to display the suburban county sticker instead.