How does CiviCRM handle international mailing addresses with unusual formats?
You can control the address format in Administer menu » Localization » Address Settings, so your mailing labels generate how you'd like.

What CiviCRM does not currently do is print different mailing label formats based on the country of the record.  I've got a proposal to a client who will fund this improvement if the proposal is accepted, but at this time I don't know.  Feel free to connect with me on https://chat.civicrm.org (name is "junglebird") if you'd like to be kept in the loop.