The CEFR Levels are a way of describing a person’s level of English. They are getting more and more popular all the time.
There are six CEFR levels: A1, A2, B1, B2, C1, C2. A1 is the lowest and C2 is the highest.
The most general way to describe the CEFR levels is as follows:
Can summarize information from different spoken and written sources, reconstructing arguments and accounts in a coherent presentation.
Can express themselves spontaneously, very fluently and precisely, differentiating finer shades of meaning even in the most complex situations.
Can express ideas fluently and spontaneously without much obvious searching for expressions.
Can use language flexibly and effectively for social, academic and professional purposes.
Can produce clear, well-structured, detailed text on complex subjects, showing controlled use of organizational patterns, connectors and cohesive devices.
Can interact with a degree of fluency and spontaneity that makes regular interaction with native speakers quite possible without strain for either party.
Can produce clear, detailed text on a wide range of subjects and explain a viewpoint on a topical issue giving the advantages and disadvantages of various options.
Can deal with most situations likely to arise while travelling in an area where the language is spoken.
Can produce simple connected text on topics that are familiar or of personal interest.
Can describe experiences and events, dreams, hopes and ambitions and briefly give reasons and explanations for opinions and plans.
Can communicate in simple and routine tasks requiring a simple and direct exchange of information on familiar and routine matters.
Can describe in simple terms aspects of their background, immediate environment and matters in areas of immediate need.
Can introduce themselves and others and can ask and answer questions about personal details such as where he/she lives, people they know and things they have.
Can interact in a simple way provided the other person talks slowly and clearly and is prepared to help.
There are many more 'descriptors' available. I suggest this document if you are interested.
CEFR stands for Common European Framework of Reference. You may notice that the descriptors are not specific to English. This framework was designed to be used for all European languages.