The federal customs administration disclosed on Wednesday that it had conducted an investigation implicating seven people.
The probe was triggered after an Italian man who drove into Switzerland at La Drossa, a border crossing in the canton of Graubünden.
He was later stopped not far away in the mountain town of Scuol, where 750 cartons of cigarettes were found piled to the roof of his SUV.
The man, who remains in detention, was questioned.
The investigation revealed that he was “addicted” to smuggling smokes, the customs administration said.
He imported an estimated 8,100 cartons of cigarettes primarily intended for buyers in Ticino.
The smuggled contraband amounted to an evasion of taxes totalling 400,000 francs ($423,000), customs said.