Your rights in case of luggage problems are mainly regulated by the Montreal Convention
If your luggage delays or disappears during the flight or you discover after the flight that the luggage is damaged, in order to fix the situation, you should first address immediately the operating air carrier or luggage desk where the report (PIR) on the event shall be prepared.
In case of the damaged luggage, claim should be submitted to the air carrier in 7 days after the event. Otherwise, the air carrier may justifiably refuse from revising your claim. If the luggage delays or is disappeared, the deadline of addressing the air carrier shall be 21 days since the time the luggage should have been delivered to you.
While filing a complaint about the luggage, you should submit the copies about the report on the event, luggage receipts and boarding cards to the air carrier and add your own claim. If possible, do not replace the damaged things or things lost from the luggage by new things before the consultation with the responsible air carrier. In case of the delay, loss or damage of the luggage, the limit of the compensation shall be 1131 SDR (Special Drawing Right) which is equal to approximately 1300 Euros.