A. In light of the legal principles, it was true that the Defendant did not return to the victim while receiving KRW 100 million from the victim I. However, at the time, the Defendant conspired to evade taxes with the victim, such as preparing a false tax invoice with the victim, and received and kept the said money from the victim. Thus, the Defendant is not obliged to return the said money to the victim as illegal consideration.

Therefore, even if the defendant refused to return the said money to the victim or used it at will, it does not constitute embezzlement.

B. The sentence imposed by the lower court (one year of imprisonment) is too unreasonable.

2. Determination

A. As to the assertion of misapprehension of legal principles, Article 746 of the Civil Act provides that "if a person pays property or provides labor for an illegal cause, he shall not demand the return of such benefit," the person who provided the benefit cannot make a claim for return of unjust enrichment from the other party on the ground that the act of the cause is legally null and void, and the ownership of the given object cannot be a claim for return of unjust enrichment from the other party on the ground that the act of the cause is the ownership of the given object, and thus, the ownership of the given object belongs to the other party to whom the benefit was paid." Here, the term "illegal cause" refers not only to a case where the act of the cause is contrary to good morals and other social order, but also to a case where the content of the right and duty, which is the object of the juristic act, is legally compelling, even though it is not contrary to social order, or the content itself is contrary to social order.