Les mystères de Sadjurah (1997)

Shabby Parisian nightclub singer Marguerite hides the rebel from the autonomous southern provinces who failed to kill the maharajah of Sadjurah. Next she's offered money to impersonate Rose, the daughter of the late French archeology professor Laurant, who discovered the treasure of the ruined ancient capital Changa. The club is torched and her unschooled preteen son Gustave 'Gus' kidnapped by a traitorous socialite arms dealer, Schwartz, and his secret accomplice, a rebel leader, to force her so as to steal the known pieces from the ruler. The real Rose offers to show them the rest of the treasure. After the switch and another bombing succeeds. The new maharajah Nadjah, mistaking her for the Rose that taught him at the Sorbonne, is spared under his enthronement pardon but Colonel Taradjahi orders her shot. Rebels attack, prevent her execution, bring her to their HQ in the lost city where she is discovered to be Rose's twin. Clever Gus mistakes Rose for Marguerite and helps her escape; she's seized by the guard but Nadjah chooses her as his maharani. The politics take over.