Level C2 corresponds to proficient users of English, who can understand and express virtually everything with ease and differentiate finer shades of meaning.
It is important to bear in mind that the Common European Framework of Reference for Languages (CEFR) is the system that defines and explains the different levels of oral and written expression and comprehension for languages such as English. It consists of 6 levels of reference: three blocks (A or basic user, B or independent user and C or proficient user), which are in turn divided into two sublevels, 1 and 2.
SKILLS AT LEVEL C2
One of the questions you might ask yourself when you read this information is, what language competences characterise a person who can prove they have a level C2 in English? The CEFR specifies the following:
He/she can understand with ease practically everything he/she hears or reads.
He/she can summarise information and arguments from different spoken and written sources, and present them coherently and concisely.
He/she can express him/herself spontaneously, very fluently and precisely, differentiating finer shades of meaning even in more complex situations.