Answer:
The French word for 'fun size' in women's clothing.
In marble halls as white as milk, lined with a skin as soft as silk. Within a fountain crystal-clear. A golden apple doth appear. No doors there are to this stronghold, yet thieves break in and steal the gold.
What is eaten but not grown and was born in water but will disappear if soaked?
Don't do this in the shallow end.
In Paris but not in France, the thinnest of its siblings.
It weighs next to nothing but no one can hold it for long. What is it?