A. We generalise Simpson's nonabelian Hodge correspondence to the context of projective varieties with klt singularities. e proof relies on a descent theorem for numerically flat vector bundles along birational morphisms. In its simplest form, this theorem asserts that given any klt variety X and any resolution of singularities, then any vector bundle on the resolution that appears to come from X numerically, does indeed come from X . Furthermore and of independent interest, a new restriction theorem for semistable Higgs sheaves defined on the smooth locus of a normal, projective variety is established.We refer the reader to [GKPT15, Sect. 5] or to the survey [GKT18, Sect. 6] for the (rather delicate) notions of Higgs sheaves, morphisms of Higgs sheaves and pull-back. Semistability is also discussed there.