A webmaster posted a new bug, at least to me, with Google Webmaster Tools at the Google Webmaster Help forums. The bug reported is that when you use diacritical mark (see here), such as words in the URL as naïve, Noël, là and so on, Google will have an issue with it.
He said that you will receive a message:
This Site May Be in violation of Google's quality guidelines. More Details.
Then you can't remove the URL due to the diacritic.
Google's JohnMu said he'd pass the bug on to the team but there are some issues with the quality of his site, at least in terms of Google's guidelines. John said:
Thanks for posting -- I've passed the problem with Sitemap files with an apostrophe in the URL on to the team. Apart from that, I agree with Webado though: I'd really recommend rethinking the model behind your site to make sure that all of your content is really unique and compelling.
Forum discussion at Google Webmaster Help.