Yes. There is currently a transaction fee of €2.00 + 2% of the withdrawal amount e.g. when withdrawing €20.00, the fee is €2.00 + €0.40 = €2.40
The fee can be at most €15.00. This means that even if you are to withdraw a large sum of which 2% is equal to more than €15.00, the fee will not surpass €15.00.
The minimum amount you can withdraw from Challengermode is €10.00.