Mac's HFS+ filesystem is case insensitive. I'm a little disappointed that Apple is so provincial and short-sighted.
$ touch "Amy"
$ touch "aMy"
$ touch "amY"
^ only one file got created
$ touch eñya
$ touch enya
So it is OK for some characters to automagically translate but it is not OK for others.
Be very careful when copying files from the Web to a Mac. One supports international alphabets in file names, the other apparently does not.