A home in south suburban Flossmoor sold last week for about 50 percent below what the sellers paid for it in 2006, a common enough story in Chicago's slowly rising real estate market. Here's what's not so common: In that same stretch of 12 years, the home's property tax bill went up by 40 percent.

The dollar amounts are different—the sale price of the house on Braeburn Avenue went down by more than $500,000, while the taxes went up $6,700 between the 2006 and 2018 tax bills.

But the criss-cross paths of prices and property taxes, with one going down while the other goes up, is a painful truth of the Chicago housing market that is most acute in the south Cook County suburbs. Tax rates in south Cook County municipalities are, on average, about twice those in western and northern towns.

"The taxes are outrageous," said Felicia Johnson, the D'aprile Properties agent who represented the buyers. "They're absolutely the reason it was on the market so long. It's a beautiful house. It's gorgeous."

The house first came on the market in February 2015 and went under contract in December with her clients, who closed their purchase Feb. 22. The buyers, whom Johnson declined to identify, were moving from another home in Flossmoor, so "they knew Flossmoor taxes," she said, but buyers looking in from other parts of the region "would say 'Oh, my God.' "

First-time buyers who go house hunting in the south suburbs "are shocked by the property taxes," said Regina Washington, a Matchmaker Property Solutions who works primarily in that area. They may not zero in on the bills until "their lender tells them, with taxes this high, you're going to have to look for houses that cost less" in order to be able to afford the total monthly cost of homeownership.