French movie?

[Lilium]

I remember seeing this movie on TV years ago, but I was in a hurry and I only watched couple of minutes of it.
I remember it had a french title even if the movie itself was dubbed.
The main character was this young girl with reddish hair, dressed in a silver or aluminium colored dress.
The setting was a forest or wood, and probably fantasy creatures, but it looked a little low buget and plastic-like.
I kinda remember this girl had a brother and she was involved in an adventure with him and other children.
I'm not sure, but maybe the title had something to do with the moon?
I know this is like impossible but maybe it will ring a bell on someone of you.
This girl was very cute and I would like to see her again!