C4 C5 C6

In the districts indicated, in any building, or portion of a building occupied by residential uses, commercial uses listed in Use Group 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 may be located only on a story below the lowest story occupied in whole or in part by such dwelling units or rooming units, except that this limitation shall not preclude the location of any such commercial use below the level of the first story ceiling, or the extension of a permitted sign, other than an advertising sign, accessory to such commercial use, to a maximum height of two feet above the level of the finished floor of the second story, but in no event higher than six inches below the lowest window sill on the second story.