Air France-KLM Connecting flights baggage allowance:

If you have a connecting flight with Air France-KLM, you can find out what your exact baggage allowance is by checking the handy baggage allowance calculator on www.airfrance.ie or www.airfrance.co.uk.
If your final destination is classified as long haul you are permitted to carry 1 baggage item free of charge subject to a maximum weight per item.
For each bag weighing more than 23 kg and less than 32 kg*, a set sum will be charged:  55 EUR
  from Europe, 100 USD from elsewhere**, or the equivalent in local currency 

More than 1 bag, (excluding Flying Blue benefits): Voyageur (AF) and Economy (KL) cabins:
2nd bag for 55 EUR
  from Europe and 55 USD elsewhere**
Additional bags: 200 EUR and 55 USD elsewhere or USD per bag.
 
In other cabins, baggage that exceeds the baggage allowance: 200 EUR
 from Europe, 200 USD elsewhere** per bag, or the equivalent in local currency Air France and KLM offers 20% discount excess baggage charges for customers who check in online (e.g.: 44 EUR
instead of 55 EUR
/ 160 EUR
  instead of 200 EUR
)

* Over 32kg: cargo transport
** Special cases: from Canada 100 CAD – 55 CAD – 200 CAD 

For further information please visit:
http://www.airfrance.ie