What is the baggage allowance for a child between the ages of 2 and 11?

For children aged between 2 years (on the date of the first flight) and 11 years (under 12 years), the baggage allowance in the hold is identical to that of an adult (baggage size: height + length + width of the baggage = 158 cm maximum).

In Economy class:
For all fares except Economy Basic, the baggage allowance in the hold is 1 piece of 23 kg on all destinations, except between Paris and Abidjan where the allowance is 2 pieces of 23 kg in the hold.
The cabin baggage allowance is 1 piece of baggage weighing 12 kg maximum. 
For Economy Basic fare, no hold baggage is included in the tariff except between Paris and Abidjan where the hold baggage allowance is 1 piece of 23 kg.

In Premium classe:
The free baggage allowance in the hold is 2 pieces of 32 kg each on all destinations. The cabin baggage allowance is 1 piece of baggage weighing 18 kg maximum.

In Business class: 
The free baggage allowance in the hold is 2 pieces of 32 kg each on all destinations. The cabin baggage allowance is 1 piece of baggage weighing 18 kg maximum.

Please note: 
The transport of a pushchair is not free of charge for children over 2 years old unless it is their only checked luggage. If you have to carry a pushchair in addition to the authorised hold baggage, you will have to pay a supplement for the transport of this 2nd baggage. You will need to purchase an additional piece of luggage.

How much does a piece of additional baggage cost?