Hello
here a quick guide
In case of definitive loss
-AF will compensate up up to 1500USD (more or less, amount based on Montreal convention signed by all IATA associated carriers ). So to optimize your time, just send invoices worth that much. In my experience AF accept all type of invoices even really old and does not apply any value discount for old items. Scan/picture are fine.
If the luggage is only delayed:
If they found the luggage, it will be send back to you.
-On your outbound flight: for luggage containing clothes they refund a certain amount to buy a change. Nothing will be paid if you buy sport accessories or rent them for the time of your stay.
On your inbound flight: no refund is given as they consider you have enough change at home.