One restaurant chain known for its bread products is suing another, alleging federal trademark infringement for use of what it calls a confusingly similar advertising slogan.

Great Harvest Bread Co. filed suit Thursday in federal court in Charlotte, North Carolina, against Panera Bread. The suit, filed on behalf of Great Harvest's more than 200 owner-operated stores, says it received a trademark in October 2014 for the mantra: "Bread. The Way it ought to be."

But the lawsuit claims that suburban St. Louis-based Panera debuted its "Food as it should be" advertising campaign just eight months later. Great Harvest, based in Dillon, Montana, says the Panera campaign intentionally causes confusion.

The Associated Press left messages seeking comment from a Panera representative Thursday.