You are responsible for any fines or tickets you get while you are renting the car, just as you would be in your own car. When you drop your car off, please let the car hire company know about any tickets or fines you've incurred.
Because driving and parking fines can take a while to come through, you may not be charged for some fines until after you have dropped off your car. The car hire company will let you know if you've incurred any fines you did not know about. They may also charge you an administration fee for this.