In the following district: beginning at the shore line of Lake Erie on the line of E. 20th St., extending southerly along the line of and including E. 20th St., to St. Clair Ave., N.E., easterly along St. Clair Ave., N.E., to E. 21st St., southerly along E. 21st St. to Euclid Ave., easterly along Euclid Ave. to E. 22nd St., southerly along E. 22nd St. to Broadway, S.E., northerly on Broadway, S.E., to Central Ave., S.E., westerly on Central Ave., S.E., to Canal Rd., northerly and westerly on Canal Rd. to Columbus Rd., northerly on Columbus Rd. to Superior Ave., N.W., thence northerly on W. 10th St. to the southerly shore of Lake Erie; any person, partnership, firm or corporation doing business may place and maintain a permanent showcase for the display of goods, wares and merchandise sold by them. Nothing in this section shall be construed to prevent the moving of goods, wares or merchandise, across any sidewalk in the way of trade, or for the use of families, and provided further, that none of the terms of this section shall be construed to permit merchandise, goods, shipping cases or other material on any sidewalk at night, on Sundays or legal holidays, or any time when the person, firm or corporation, owning or controlling the property fronting on the sidewalk, has closed its place of business or ceased the actual work of shipping or receiving merchandise, goods, shipping cases or other material.