Flat Bundles With Complex Analytic Holonomy

Let G be a connected complex Lie group or a connected amenable Lie group. We show that any flat principal G-bundle over any finite CW-complex pulls back to a trivial G-bundle over some finite covering space of the base space if and only if the derived group of the radical of G is simply connected. In particular, if G is a connected compact Lie group or a connected complex reductive Lie group, then any flat principal G-bundle over any finite CW-complex pulls back to a trivial G-bundle over some finite covering space of the base space.