Today, security is at the forefront of every legal system's concerns. One of the most important aspects of security that will make citizens feel comfortable is the provision of judicial security. Judicial security, is, the safeguards of the rights, property, rights, dignity and rights of all citizens. What are the proper mechanisms for achieving this and ensuring the judicial security of the citizens, especially the accused? What steps did the legal systems in this research take and what legal measures did they anticipate? Providing judicial security in the light of the principles of fair and equitable trial and the presence of independent and impartial judges in judicial authorities and observing their defense rights such as the principle of acquittal, the right to have a lawyer and their understanding. Observance of the principle of acquittal and adherence to it and the presence of a lawyer in the criminal process, in addition to being known as an assistant to the judge, is also instrumental in the administration of justice, a focus of the Iranian and French legal system and a major focus of international documents, including the Universal Declaration of Human Rights ( Located 1948). According to Iranian Criminal Procedure Code, no one should be summoned or summoned as a defendant without sufficient reason to attribute the charge. This regulation refers to the principle of absurdity and provides for judicial security in which citizens can be protected from any prosecution and, on the other hand, defend themselves if they are charged with a lawyer. Given the importance of the lawyer in the criminal process, the presence of a lawyer in all stages of the Iranian and French legal system is anticipated. Given the importance of the lawyer in the criminal process, the presence of a lawyer in all stages of the Iranian and French legal system is anticipated. In this paper, using the descriptiveanalytical research method, the role of "defense rights", in particular the right of the accused to have a lawyer in providing "judicial security", is studied.