PRINCETON - A Princeton-based consumer attorney is accusing a popular donut and coffee chain of overtaxing New Jersey customers.

Carl Mayer filed a class-action lawsuit on behalf of a Fort Lee couple who says they were overcharged at the Dunkin’ Donuts on Route 46 in town. According to the lawsuit, the Fort Lee location and other Dunkin’ Donuts locations across New Jersey knowingly charged customers sales tax for bottled water. Bottled water and packaged coffee are exempt from the 7 percent New Jersey sales tax.

“We found this all over the state of New Jersey,” says Mayer. “The tax is not permissible and other national franchises don’t do this.”

Mayer says it’s happened at Dunkin’ Donuts locations in Princeton, Lawrenceville and Chatham as well.

A spokesperson for Dunkin’ Donuts issued a statement that said the company is “in the process of reaching out to the franchisees identified in the complaint in order to determine whether these taxes were charged to customers.”

The spokesperson also said that all franchisees are expected to comply with all laws.

Anyone who thinks they were wrongfully taxed is urged to join the class-action suit or shop elsewhere.

Attorneys are filing a similar class-action lawsuit in New York.