"Eiffel" filmmaker Martin Bourboulon is currently in pre-production on the double project, which will star Francois Civil, Green, and Cassel as D'Artagnan, Milady, and Athos, respectively.
The first feature will be titled "The Three Musketeers - D'Artagnan", while the second will focus on Milady, and both are based on the French literary classic by Alexandre Dumas.
The cast and crew will shoot the films simultaneously in France in late summer, reports Variety.
Others set to appear in the new swashbuckling take on "The Three Musketeers" include Oliver Jackson-Cohen as Britain's Duke of Buckingham, Vicky Krieps as Queen Anne of Austria, and Louis Garrel as King Louis XIII.
The Dumas novel has repeatedly been adapted into film, with Gene Kelly and Angela Lansbury featuring in a 1948 movie, while Charlie Sheen, Kiefer Sutherland, and Chris O'Donnell starred in a 1993 Disney version.
Besides landing a role in the new "Three Musketeers" movies, the actress is attached to a new sci-fi thriller "A Patriot" where she is expected to share screen with the likes of Helen Hunt, Charles Dance, and Scot Williams.