dissenting. I am unable to concur in the ruling made in the third headnote, and am therefore forced to dissent from the judgment of reversal. The trial judge, under the pleadings and the evidence at the hearing for temporary injunction, found that, contrary to the statute under which the city was acting, it sold the bonds at less than par. The statute in question is mandatory, as follows: “Said bonds shall be sold at not less than par, . . or such bonds in the amount that shall be necessary for that purpose may be turned over and delivered to the contractor at par value in payment of the amount due him on his contract,” etc. It appears to me that the evidence demanded the finding that the bonds were sold at less than par. The paving contract entered into between the City of Bainbridge and the paving contractor, whereby the bonds were turned over and delivered to the contractor at less than par, was therefore an illegal and invalid contract. “In a case of the character just indicated, no estoppel will arise against *516an abutting-property owner, on account of the fact that the pavement was completed before the filing of the petition, to deny the validity of the assessment, especially where such property owner entered his protest against the construction of the improvements.” Sanders v. Gainesville, 141 Ga. 441 (1 a, b) (81 S. E. 215). Moreover estoppel is not pleaded as a defense, and therefore the judgment of the trial judge should not be reversed on the ground that the petitioners were estopped. The opinion of the trial judge, with authorities cited, is set out above, and it is sound and convincing. The principles ruled in the first and second headnotes are in accord with previous decisions of this court. While this is true, manifestly they sanction a new encroachment upon the property rights of private citizens. It is indirect taxation hy the municipality under a method not foreseen by the framers of the Georgia constitution. The power of cities to incur debts is strictly limited, under the constitution of Georgia. Clearly this, even though legal, is an ingenious method of avoiding the constitutional limitations by doing indirectly what the city could not do directly. In such a case the statute should be strictly construed, certainly as much so as if the city were incurring a liability against the municipality itself in the usual way. In City of Thomasville v. Light Co., 122 Ga. 399 (50 S. E. 169), this court said: “The policy of the law of this State is, and has been since the adoption of the present constitution, opposed to the incurring of debts by towns and cities; and it has therefore become the settled rule that all laws in reference to the course to be followed by the public authorities in obtaining consent to contract a debt in behalf of the taxpayers are to be strictly construed, and the consent of the taxpayers is never held to have been given in any case unless the requirements of the law providing the manner in which the debt shall be incurred have been strictly complied with in every material particular.” Mays v. City of Jackson, 147 Ga. 556 (94 S. E. 1006). In this case assessments were made by the municipality on the private property of citizens for public uses, and the principles of estoppel should not be applied to them as in the cases cited in the majority opinion, where improvements were made on the property of the owner for the personal benefit of the owners of the property. Here the contract on which the assessment is made was illegal, because contrary to the express mandatory provisions of the statute under which the *517paving was authorized. The paving contractors were bound to know that the contract was illegal. They had. already perfected an arrangement with the local bank to receive the bonds far below par; and there was evidence for the petitioners that the paving improvements were made over their protest and objection. While courts are and should be slow to interfere with public improvements, at the same time the solemn duty rests upon them to protect private property of the citizen1; for the constitution, article 1, section 1, paragraph 2 (Civil Code (1910), § 6358), provides: “Protection to person and property is the paramount duty of government, and shall be impartial and complete.”