The topic of this final paper is "Tax secret". Any information known only to a certain number of persons shall be considered a secret and shall not be passed on as such. This paper will explain and analyze the concept and types of secrets defined by the Data Protection Act and the Law on Data Confidentiality. After that, the tax secret is analyzed, which is an institute of tax and legal procedure that has its exceptions. Tax secrecy serves to protect the debtor's privacy and protect his interests so as not to cause him moral and material harm. The paper contains an overview of the General Tax Law, which analyzes articles that regulate tax secrecy, and exceptions to the obligation to keep tax secret with the examples given from practice and opinions of the Central Office of Tax Administration. The paper will touch on and analyze the publication of a list of outstanding debts. After that, the difference between the tax secret system in the three selected countries is analyzed. Germany, France and the US have different views on tax secrecy, so we will see how a country has resolved the problem of keeping information learned and the tax process, and in which cases officials may intervene and release or transmit this information to the competent institutions to protect national interests.