The City of Missoula lost a case at the Montana Supreme Court this week against a woman who challenged a local surcharge of $25.

Defendant Corinne Franklin was in Missoula Municipal Court back in 2015 accused of misdemeanor Disorderly Conduct. She pleaded no contest and was then fined $100. She had to pay the costs of prosecution, which was another $50, as well as a list of various surcharges that totaled up to another $110.

$25 of those surcharges were directed to help fund the City Attorney’s office by an ordinance signed by Mayor John Engen back in 2013, but the State Supreme Court found that the city didn’t have the authority to do that.

In its decision, the State Supreme Court writes that the City of Missoula “offers no reasoned basis to afford a municipal court greater authority under a local resolution or ordinance to add penalties for a state-law sentence. Under the city’s reasoning, it could impose an additional fee of unlimited amount or mandate additional jail time for violations of state law.”

Franklin’s $25 may not sound like much, but it could end up costing the City of Missoula nearly half a million dollars. According to NBC Montana, the attorneys that won case are preparing a class action lawsuit over the matter.