I need someone to write this, and desperately.
So, it's post-hawkmoth, either pre or post-reveal, and France is celebrating their heroes victory.
Then, the French government comes together and decides that France would be a lot safer if they had better leaders. Or, a monarchy.
They then decide that they want to have monarchs again, and who better to rule France than its own protectors, Ladybug and Chat Noir?
So, they ask Ladybug and Chat Noir to become the official King and Queen of France.
Then the whole fic is just them trying to figure out how to rule a country.
If anyone does end up writing this, please tag me. I'd love to read it!