The plaintiff's appeal is dismissed in entirety.

Expenses for appeal shall be borne by the plaintiff.

Purport of claim and appeal

The first instance court.

1. The reasoning of the court’s explanation concerning this case is as stated in the reasoning of the judgment of the court of first instance except for the corresponding part of the judgment of the court of first instance as stated in the following paragraph (2). Thus, this is accepted in accordance with the main sentence of Article 420 of the Civil Procedure Act.

2. Part II of the decision of the court of first instance (No. 5, No. 19 through No. 8, 7) which has been written by the court of first instance shall be as follows:

"B. 1) Taxes such as the registration tax and the acquisition tax and the tax return method are, in principle, the specific tax liability is determined by the taxpayer's act of determining the tax base and the amount of tax, and the payment act is the specific tax liability determined by the report.

Since the State or a local government holds the tax amount paid based on the tax claim so finalized, it cannot be deemed as unjust enrichment unless the taxpayer’s filing of a tax return is void as a result of a serious and obvious defect.

Here, whether a defect in the act of reporting constitutes the invalidity of the law because it is significant and apparent should be determined reasonably by considering the purpose, meaning and function of the law that serves as the basis for the act of reporting and the legal remedy for the defective act of reporting, and by individually identifying and determining the specific circumstances that arise from the act of reporting.

(see, e.g., Supreme Court Decision 2011Da91470, Jul. 25, 2013). In order for a tax disposition to be null and void as a matter of course, the mere fact that there is an illegality in its disposition is insufficient, and the defect is in violation of important laws and regulations, and should be objectively apparent. In determining whether the defect is significant and obvious, the purpose, meaning, function, etc. of the relevant tax disposition should be considered as a purposeological basis, and at the same time, the specificity of the specific case itself.