Iranian laws about rent and especially commercial places, despite major changes in legislation, due to the lack of clear definitions in various fields of above issues, have made the courts and lawyers in its use with problems, because the legislative approach about the landlord and tenant relations in the years, 1977 and 1997 have been such that each is somehow violated previous laws, while each of these rules in its own sphereis still applicable. This leads to different interpretation of the rules, and consequently, disagreement between the lawyers. One of the conflicts is related to the right to acquire the goodwill and trade, which already there are confusions between lawyers in this regard. Therefore, these issues cause fundamental problems in the way the law is written. To find suitable solution for these problems, because, Civil law which reflects the French law completely, according to influence, in the law of many countries and leading to the establishment of these relations reasonably and in accordance with demands, in this study, it is studied in a comparative study of the laws of the country to achieve more reasonable results in this field. Of course, as we shall see, despite the apparent similarities between the landlord and tenant laws of Iran and France, there are practically fundamental differences (even in the definitions) between the two laws, which in the present study has attempted to study controversial issues related to this matter of the law.