What if Napoleon I remained Emperor?

How would the 19th C. and beyond be affected? Would Nationalism take hold in 1848? Would the demise of Austro-Hungary happen sooner? Would the Franco-Prussian War of 1870 occur?

Let’s assume Napoleon won at Leipzig and was able to strike a peace settlement, hold his throne, and therefore protect his line. My thought process is the peace would have been temporary regardless, but let’s assume it held.

Would Germany never take shape? Would World I or World War II never happen? Would NATO never form?

So many what-if scenarios…