Names starting with letters with accents, like É (eg Édith Piaf) go to the end of all items (after the letter z) in Mac version of MC. Édith Piaf is listed at the end of all artists in the alphabetical order, for example.
Afaik, in English, modified letters (such as those with diacritics) are treated the same as the base letter for alphabetical ordering purposes, so Édith Piaf should have been listed among other artists starting with E, irrespective of the accent (before Eduardo Delgado). It would be the same in French.
JRiverMC Windows version seems to have felt safer by treating all modified letters with diacritics as separate letters and collating them immediately after their unaccented counterparts. (É after E, Ü after U etc.) As a result Édith Piaf goes to the end of all artists starting with E, and placed just before F. This may be because there are different extra letters in different languages and thereby different conventions for alphabetical order.
I think this treatment of modified letters by the Windows version of MC is fine. However, listing all modified letters at the very end of the alphabet, like the Mac version of MC, is not acceptable. I think Mac and Windows versions of JRiverMC should be consistent, at least, and this issue should be corrected in a future update of Mac version.