It depends which camping vehicle you want to rent. You'll find the requirements for the driver license class in the vehicle profile under "Overview".
Be aware that with caravans there are some special rules. With a B driver license you can tow a caravan up to 750 kg, or you can tow a caravan which total weight combined with the total weight of the towing car does not exceed 3.5 tons. For heavier caravans you'll need a BE license.
For our insurance you need to have had a valid driving license and the right qualifications for at least 3 years and be registered in the EEA, the United Kingdom or Switzerland. Your driving license must also be issued within the EU, United Kingdom or Switzerland.