In Germany, drivers from foreign countries only need their driver licenses (DLs) issued by their respective home nations. For cases when your DL is not in English – or in any other Latin language – you would need an International Driving Permit (IDP). Some suppliers make it mandatory because, in cases of accidents, the police officer usually ask for it especially when your DL is not in English; they’d need it to fill the accident report form. IDP only acts as the translation; if you only have the IDP and not your DL, you will not be allowed to pick the car.