At any time after the assessment book or roll has been received by the tax collector, and the taxes have become payable, the owner of any property assessed therein, who may claim that the assessment is void in whole or in part, may pay the same to the tax collector under protest, which protest shall be in writing, and shall specify whether the whole assessment is claimed to be void, or if a part, what portion, and in either case the grounds upon which such claim is founded; and when so paid under protest the payment shall in no case be regarded as voluntary payment, and such owner may at any time within six months after such payment bring an action against the city, in a court of competent jurisdiction to recover the tax so paid under protest; provided, however, that no recovery shall be had in any such action unless such action is brought by such owner or his guardian, or in case of his or her death, by his or her executor or administrator, and; provided further, that no recovery shall be had in such action if the same is brought by an assignee of such owner, or by anyone other than the persons last designated above in this section, and if it is adjudged that the assessment, or the part thereof referred to in the protest, was void on the ground specified in the protest, judgment shall be entered against such city therefor. (Prior code § 6.04.1020)