I'm working on a story at the moment, and one of the background details I'd like to include is the Holy Roman Empire being equivalent to OTL France, rather than OTL Germany. What would need to have happened to keep the Roman crown passing through the successors of Charles the Bald rather than the East Francian kings? How would this change have altered the political landscape in Medieval Europe? Would a French Holy Roman Empire be able to last? What would become of Germany, England, and the Iberian peninsula?