(CHICAGO) A lawsuit filed Tuesday accuses McDonald’s of overcharging customers when it calculates the added sales tax on the sweetened beverages it sells in Cook County.

The suit is being brought by Yvan Wojtecki and seeks class action status on behalf of other customers who were overcharged for their drinks at McDonald’s locations in Cook County.

On Tuesday, Wojtecki bought food and a sweetened beverage at a McDonald’s restaurant and paid 23 cents under the county’s Sweetened Beverage Tax, according to the suit.

Wojtecki claims McDonald’s added the 23 cent tax to the pre-tax price of the beverage as a surcharge. The subtotal for the food, beverage and tax was then taxed again at the county’s sales tax rate when the final total for his purchase was calculated.

McDonald’s violated the consumer fraud act by charging sales tax on a subtotal that included a charge meant to be collected for the sweetened beverage tax, according to the suit.

Wojtecki seeks compensatory damages, re-payment for the costs of bringing the suit and any other relief the court grants him. A jury trial is requested.

The number of customers harmed by the way McDonal’s has added the tax to their orders is currently unknown, according to the suit. If granted class action status, other customers who could have been harmed would be contacted by mail, email, internet postings and/or published notice.

Cook County’s Sweetened Beverage Tax went into effect Aug. 2 after a monthlong delay and charges a penny-per-ounce tax on sweetened drinks.

Walgreens was sued Monday in Cook County court after a consumer found he was charged the tax when he purchase two unsweetened drinks at its stores.