PARIS, April 19 — After a colossal 16-year restoration effort, Abel Gance’s seven-hour silent classic Napoleon will finally return to the big screen at the Cannes Film Festival in May, organisers said Thursday.

The project to restore the epic 1927 film began in 2008 when two film researchers discovered different versions of the film in Gance’s archives at the Cinematheque Francaise in Paris.