Originally Posted by
CPH-Flyer
IHowever their inability to charge the fee at the gate does seem rather unreasonable.
I agree. Normally, airport staff elsewhere has no issue extorting hundreds of Euros at the gate for oversized hand luggage on FR flights. I believe often such luggage is gate checked, i.e. getting into the hold, if exceeding the dimensions for (paid) hand luggage with FR.
But IDB? No, because you brought hand luggage that you hadn't paid for.