Help Me:Unify Germany and Republicanize France without OTL's FPW

I'm planning on a TL which involves having the French be successful in setting up the 2nd Mexican Empire. But due to my research and given info from other members I understand that this will butterfly away the cause of OTL's Franco-Prussian War, German Unification, and formation of the 3rd French Republic. Since focusing on the alternate histories of France and Germany are not my main focuses for my TL but are obviously going to be affected can you please help me to have both countries take on forms similar to those they had in OTL after the FPW? They don't need to have governments exactly like the ones of OTL but just enough to wher I don't have to invest too much time writing detailed histories for these countries in my TL when I'd rather focus on others.
 
France : relativly uneasy. Still : having repetitive scandals likeVictor Noir murdering, maybe financial ones tied to Mexico or foreign project (Panama Scandal like) with an economical crisis could led to a reject of the Empire.

I would see it beggining by an uprising in Paris and republican/workers strongholds, and a referundum won (but quite difficulty) by opposants.

Germany : more easy. Northern Germany was de facto the same than II Reich, except no southern German states.
If you don't need Bavaria and Baden united. It's done.
If you need them, have Prussia supporting unionists in these realms. In the medium term, it's won.
 
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