The Purple Mask

The Purple Mask is a 1955 American swashbuckler film, starring Tony Curtis and set in 1803 France.

The lovely Laurette de Latour, niece of a marquis and romantic interest of Captain Laverne, is on the side of the royalists. She helps hatch a scheme in which the foppish Rene de Traviere, who seems able with a sword, impersonates the Purple Mask to infiltrate Napoleons ranks and free her kidnapped uncle.Laurette is unaware that Rene is, in fact, the Purple Mask, who continues his charade, drawing ridicule on himself, until ultimately he is imprisoned along with the marquis. Laurette discovers his true identity while imprisoned and she faints. ........

Source: Wikipedia