C2 | Proficiency. Can understand with ease virtually everything heard or read. Can summarise information from different spoken and written sources, reconstructing arguments and accounts in a coherent presentation. Can express him/herself spontaneously, very fluently and precisely, differentiating finer shades of meaning even in more complex situations.
This is a companion discussion topic for the original entry at http://grammarerror.com/tags/cefr-c2