If you have requested a registration, a paid admission or an LEZ day pass for the day to which the fine relates, as a minimum, you have to produce the approval e-mail or the proof of purchase of the LEZ day pass. It should clearly show that the registration, purchased admission or LEZ day pass

The driver is responsible for entering the correct Vehicle Registration Plate during registration, when applying for admission or when purchasing an LEZ day pass. The administrative fine is still owed in case of error.