Most Rental Car companies require a Credit Card on arrival. The security deposit is ¨held¨ on the card and not withdrawn, for the duration of the hire and released when the car is returned without any claims or damages. Credit Cards provide a higher level of security for the rental car supplier, as opposed to a Debit Card.
Some rental car companies might accept a Debit Card but you must have enough ¨credit¨ on the Debit Card to cover the Excess insurance amount. This Excess amount can vary wildly between 300-3000€ in certain countries. The Excess amount will be withdrawn from your debit card when you arrive.