Maria Titus owned the 25-foot wide house at 15 East 12th Street in 1870. It sat within a fashionable neighborhood, just two blocks south of Union Square and half a block from Fifth Avenue. On April 28 that year she sold the "elegant residence" to Thomas O'Connor for $18,000. (The price would equal about $368,000 today.) O'Connor renovated it into a French flat. The term was used to differentiate upscale apartment houses--still viewed skeptically by most families--from tenement buildings.
To Let--Part of a French Flat (four rooms) unfurnished, with use of kitchen, range, hot and cold water, washtubs, privilege of bath, water closet, elevator and all conveniences to a gentleman and wife; rent $35 per month; only one other family of two in the house, with other.