Each person, firm or corporation maintaining such sign, signboard or rigid canopies temporarily or permanently, shall file with the clerk a bond or indemnity policy in the sum of fifty thousand dollars ($50,000.00), conditioned to indemnify the city for any loss or damage or liability that may result from the construction or maintenance of such sign or canopy; provided, that if the city has secured a blanket policy to protect against such risks then no such bond shall be required. (Prior code § 33-4-4)