A person with C2 gets a lot of praise and compliments whereas a native doesn't. 

I think a lot of C2 can know more gramar for a lot of native Speakers, but not everyone, becuase for example there are a lot of native Speakers that know the grammar of their langueges, so they can write and speak very clean.

I'm sorry, I meant:

You can read more about it here:

Hi Niki, it's the highest level in the learning of a second language (Mastery or Proficiency) according to the CEFR (Common European Framework of Reference for Languages).

You can more about it here:

☛ http://en.wikipedia.org/wiki/Common_European_Framework_of_Reference_for_Languages

☛ http://www.italki.com/p/oet.htm?src=italki-footer

Hope this helps you!

May I ask what is C2?