The ads that have run thus far in Chicago's mayoral race have been positive and show the candidates talking about themselves and their platforms.
A new ad out Friday by Gery Chico changes that.
Emanuel has proposed cutting the city's sales tax by a quarter of a percentage point. The tax, however, would be expanded to included other "luxury goods," -- things like limo rides, pet grooming and other services.
Chico, who does support some tax proposals, such as an etailer tax, is critical of Emanuel's tax plan.
In the ad, Chico equates the Emanuel's plan -- which he calls "The Rahm Tax" -- to the highly unpopular and controversial one percent sales tax pushed through in 2008 by then-Cook County President Todd Stroger.
"If you thought the Stroger sales tax was a killer, you’ll hate the Rahm Tax," a narrator says in the ad.
Emanuel responded to the ad after accepting the endorsement of the Sierra Club.
"My view is to attack the problems that are facing the city of Chicago, not attack each other," said Emanuel. "It's been over a week since Gery decided to announce any new ideas, except for criticizing an idea he once agreed with."
The Chico campaign, however, pointed to a proposal to bring the Super Bowl to Chicago that was floated last week.
Watch Chico's ad: