It is thought to be the first big pay-out since the pounds 3.60 an hour floor was introduced on 1 April.
The restaurant chain infringed the law by counting cash tips as part of workers' wages. Only non-cash gratuities can be included in the calculation.
Ian McCartney, the Trade minister, said there would be "no hiding place" for companies that break the minimum wage law.
There are a number of cases involving household names which could lead to "enforcement" proceedings, he said. The Inland Revenue's "help-line" had received nearly 2,000 complaints, of which some 762 had been resolved. Hundreds of companies have also called to shop low-paying competitors.Reuse content