The appeal is dismissed.

The costs of appeal are assessed against the Plaintiff.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. As to the grounds of appeal Nos. 1 and 3, the court below, in order to revoke a juristic act on the ground that the motive mistake constitutes an error in the important part of the contents of the juristic act, it is sufficient to acknowledge that the motive is the content of the pertinent declaration of intent to the other party and that it is the content of the juristic act in the interpretation of the declaration of intent, and it is sufficient to conclude that there is sufficient reason to conclude that there is an agreement between the parties on the motive of the juristic act separately, but the mistake in the contents of the juristic act would have been deemed to have been an important part to the extent that it would not have

(2) In light of the above legal principles, it is difficult to recognize the fact that the Plaintiff entered into the instant agreement with the Defendant that the imposition of school site charges corresponding to the “third party allotment due to cash settlement” among the general apartment units newly built under the redevelopment project is in violation of the principle of equality, and that the imposition of school site charges corresponding to the “third party allotment due to cash settlement” is in violation of the principle of equality. However, even if the Plaintiff entered into the agreement with the Defendant that donated the extended cost in lieu of the school site charges, the evidence submitted by the Plaintiff alone is insufficient to recognize the fact that the amount of the school site charges corresponding to the “third party allotment due to cash settlement” out of the amount of the contribution made by the Plaintiff in lieu of the school site charges is very large in the amount of the contribution made by the Plaintiff, and even if the Plaintiff grants monetary burden to a certain extent rather than the school site charges, it is expected that the Plaintiff’s children will enjoy prompt progress of the redevelopment project and that the existing specific school adjacent to the instant redevelopment project site.