To prevent another big sign like the one Donald Trump attached to his riverfront skyscraper, Mayor Rahm Emanuel is introducing an ordinance allowing new signs along the waterway but substantially reducing their size.

Last June, through a spokesman, Emanuel called the Trump sign "awful" and in "very poor taste," prompting international media coverage of the war of the words waged by the brash Chicago mayor and the brash New York developer and TV reality star.

Now, unable to remove a sign that his administration greenlighted, Emanuel wants to stop any repeats by regulating the size, placement and materials of high-rise signs along the downtown waterfront.

Emanuel is proposing a protected zone, to be called the Chicago River Corridor Special Sign District. Had this been in place before Trump received permission for his sign, its size would have been cut by more than fivefold, from the 2,891 square feet that was allowed to 550 square feet, city officials said. The developer also would have been forced to place the sign directly beneath the building's highest roofline - some 1,100 feet up - instead of the sign's current location about 200 feet above ground, where it looms over the heavily trafficked Michigan Avenue bridge.

The idea of sign restrictions along the river has its critics, including property rights advocates who say owners should be free to treat their buildings as they see fit. Trump himself has said the public loves his sign.

Emanuel has framed the matter as a way to ensure that Chicago's downtown Riverwalk, which he envisions as a recreational showplace lined with trees, walking paths and restaurants, is not marred by Las Vegas-style excess. Construction workers are now extending the Riverwalk in a six-block area from State Street to Lake Street. The $100 million project is expected to open in 2015.

The proposed sign ordinance says it would ensure that new signs "do not detract from the character of the area, do not have a negative impact on the area, and do not create visual clutter."