At Level B1, you are able to express yourself in plain and coherent language when talking about familiar topics and personal interests. You can also describe things you have experienced, describe goals and explain your views. You have a command of the essential grammatical structures.
At the B2 level, you can express yourself clearly and in detail, and successfully argue a point and negotiate. You have a large vocabulary in your field of specialization and most general topics of discussion. You have a good command of grammar.
You can express yourself spontaneously and fluently. You are familiar with colloquial phrases and know how to use various language styles. You have an excellent command of grammar.