Technically speaking, the felt is supposed to be used Only for transportation purpose and should not be given to customers. Some SAs in France who has been working there for tens of years is a stricter for this "rule" no matter how much you ask for it, but as we all know with H, a so-called rule does not mean it will be applied everywhere in the world.
Some SAs will downright refuse to give you a replacement felt, but most of them will say it nicely as in: when I have one, I'll keep it for you, etc etc.
I know how you feel about wanting the felt, I feel the same way too, but accepted that some of my bags does not have the felt cause the SAs threw it out. Not worth the aggravation and time of "asking" for a felt cause I know what they'll do (or not do in this case).
My suggestion to you is try to ask your SA anyway, no harm to ask but don't have your hopes up too high dear. Sorry...