Here’s a detail of the ceiling. Every stroke of the brush pure renaissance? Nah. The church was heavily hit by bombs in World War II, and the ceiling was damaged. The restoration work can only have been from photographs.
Still, I suppose it’s pretty accurate in places where photos existed. Together with the overall style and whatever color existed in burned fragments, it might have been possible to recreate the impression the church gave before the bombings.
Of course, this might still be far off the original. Just think of all the baroque alters that have replaced their gothic predecessors, even without wars.