SEATTLE – The International Franchise Association wants to take its challenge of a Seattle law raising the city’s minimum age to $15 to the U.S. Supreme Court, CNBC.com reports. In June 2014, the Seattle City Council approved the $15 minimum wage, which was structured to rise in increments. The federal minimum wage is $7.25.

Like New York City, Seattle lumped smaller franchised companies in with larger businesses, and thus subjected to a faster schedule of raising the minimum wage. Companies with at least 500 workers must have the $15 minimum wage in place by 2017, while other businesses have until 2021 to raise the minimum wage for their workers to $15.

The association, along with five Seattle franchisees, filed a lawsuit against the city, arguing that the higher wage is unfair for franchisees, which are essentially smaller businesses. “Our appeal has never sought to prevent the City of Seattle's wage law from going into effect,” said franchise association president Robert Cresanti. “Our appeal to the Supreme Court will be focused solely on the discriminatory treatment of franchisees under Seattle's wage law and the motivation to discriminate against interstate commerce.”

Last March, a federal judge tossed the franchise’s lawsuit, with that decision upheld by the Ninth U.S. Circuit Court of Appeals in September. The association expects a response from Seattle within the month, while the Supreme Court will make a decision this spring on whether it will hear the case.