Go to the following URL with "French" as browser/mMdiawiki UI language:
You get an error (which is normal):
Wiki checks did not pass
Make sure that you are logged in or contact an administrator in order to be granted permission to view this page (Vous ne faites pas partie d'un groupe ayant le droit d'uploader par URL.).
The problem is the apostrophe characters are invisible and replaced with '. So with have some escaping/unescaping problem with UI messages.