The Million Dollar Baby star had been in a taxi stuck in a traffic jam when the thieves struck.
Police confirmed that three robbers attacked the vehicle in the northern suburb of Saint-Denis on Friday morning (January 18), reports Sky News.
They smashed the back window and snatched the actress's designer handbag out of her hands.
Saint-Denis is renowned for smash-and-grab robberies due to regular traffic jams in the area.
Oscar winner Swank will soon be appearing on UK screens in Mary and Martha, a TV film about mothers bereaved by malaria written by Richard Curtis. The film will air in the run-up to this year's Comic Relief in March.