국세기본법과 관세법상 중복조사 금지에 관한 비교연구 - 대법원 2015. 2. 26. 선고 2014두12062 판결 및 대법원 2020. 2. 13. 선고 2015두745 판결을 중심으로-

In principle, dual investigations should be prohibited because they seriously infringe on the freedom of business and legal stability of taxpayers, as well as lead to abuse of tax investigation rights. The Framework Act on National Taxes and the Customs Act explicitly set out regulations on the prohibition of dual investigations. Regarding the prohibition of dual investigations, issue such as ‘a method of determining the duplication of investigation to which the principle of prohibition of dual investigation is applied’ is usually raised. In this study, precedents related to the Framework Act on National Tax (Supreme Court 2014du12062 judgment, etc.) and customs law precedent judgments (Supreme Court 2015du745 judgment) were examined in turn on the issue. In particular, the 2015du745 decision of the Supreme Court is significant in that it is the first Supreme Court ruling on the prohibition of dual investigations under the Customs Act. There is a difference between the two laws in the above issue regarding the judgment of ‘duplication of investigation’. This is because there is a difference in wording, such as the Framework Act on National Taxes using ‘same item of taxes’ and ‘same taxable period’ as the criteria for determining redundancy, and the Customs Act using ‘the relevant case’ as the criterion. At this time, attention should be paid to the interpretation in that ‘the relevant case’, which is the standard for determining redundancy under the Customs Act, is an indeterminate concept open to interpretation. Judging from the meaning of the Taxpayer Protection Ordinance of the Korea Customs Service, the prohibited overlapping investigation means “re-investigation in the same field of customs and legality and the same period subject to investigation.” In the case of the Supreme Court’s 2015du745 rulings, the customs authorities chose a different method of determining the tax price in detail in each preceding and trailing investigation, but eventually conducted a “reexamination of the same customs clearance legal field.” Consequently, the conclusion of this judgment, which constitutes an illegal duplicate investigation, is reasonable in light of the above Korea Customs Service ordinance. In order to clarify the meaning of ‘the relevant case’, which is the standard for determining the overlap of investigations under the Customs Act, a legislative review was also conducted, such as whether the contents of the Korea Customs Service ordinance need to be reflected in the Customs Act. It is important for both taxpayers and tax authorities to familiarize themselves with the attitudes of case law regarding dual investigation. If the taxpayer determines that the investigation by the taxation authority falls under a “dual investigation” in light of the existing precedent attitude, the taxpayer can obtain relief by using the taxpayer protection system or by filing a lawsuit or a trial to cancel the imposition of the imposition. In addition, the tax authorities can judge whether the above taxpayer’s argument is valid by referring to the existing precedent attitudes.