If you would like to witness the forces of colonialism in brute action, Rithy Panh’s extraordinary new film provides the long view. A masterpiece of editing, the film assembles archival footage and antiqued title cards into a wordless recapturing of the Indochinese Empire, beginning with the early days of French occupation. In this prelapsarian age, everything is golden with promise. Ladies, in empire waist gowns and enormous hats, throw candies to local children. Great steamships carry French culture abroad, and the Tricolore flag flies on high.