A small surf on the FB site and I find that I am wrong.
At
http://eshopping.airfrance.fr you can spend your miles in return for jewellery, fluffy toys etc.
And with KLM you can shop in the air buying those perfumes from the back of the magazine, using your miles at 17000miles = Euro50:-
or Euro735 for your 500k.
That would solve the problem of your mother-in-law's Birthday present until 2025. Probably.