'Tis simple, have Napoleon III take his empire to victory in Mexico and the Franco-Prussian War as well as general diplomacy and use that to build a French Empire that dominates Europe.
Bonus points for incorporating Spain, Gibraltar, Belgium, a surviving Ottoman Empire, a big chunk of Germany, and so forth.
Extra bonus points if you can have the world outside Europe occur much as it did OTL.
(If anyone has read Jon Courtenay Grimwood's Clare Fabio novels, that's where I'm taking this from.)
Bonus points for incorporating Spain, Gibraltar, Belgium, a surviving Ottoman Empire, a big chunk of Germany, and so forth.
Extra bonus points if you can have the world outside Europe occur much as it did OTL.
(If anyone has read Jon Courtenay Grimwood's Clare Fabio novels, that's where I'm taking this from.)