126. A marriage can be impugned for the cause 5 specified in article 123 only on behalf of a party who was unaware of the incompetency of the officer, and for the causes 2, 3, 4 specified in the same article only on behalf of the party who was not free, or was of unsound mind or in error, and for cause 6 only by a parent, tutor, or curator of one of the parties, who was a minor or interdicted at the time of the marriage, such parent, tutor, or curator having been ignorant of or having refused consent to the marriage.