Accidents, disputes with the neighbor, thefts, crimes are all matters that the criminal lawyer can defend in court. Initially, this expert in legislation constitutes a file made up of reports, expert opinions, testimonies … He talks with his clients in his office, or meets the defendants in pre-trial detention in prison. His argument must be prepared with care, because a relevant argument is essential to convince judges and jurors. The lawyer can be generalist or specialized. Thus, business lawyers advise companies during mergers and divestitures, and defend their interests in the event of litigation. Practicing in a liberal capacity, the lawyer works alone or with collaborators within a firm. The profession has a minority of employees. To practice, the lawyer takes an oath and registers with a bar.