I’m mildly surprised that a Paris airport (I take it the airport referenced is CDG) shows only Athens and Αθήνα – English or Greek spelling – if they’re going to be ‘multicultural’, I’d expect a French airport to alternate between Athens and Athènes and Αθήνα …
Obviously this is trivial to implement, software-wise, but IMHO it’s merely cosmetic. English is not only the language of civil aviation, it’s the language of international travel. A Russian or Japanese person travelling to Athens, outside their own country, will expect to look for the word Athens as spelt in English, not Αθήνα nor Афины nor アテネ nor even Athènes.