In other words, the guy was basically a real-life version of the accident-prone Inspector Clouseau from the Pink Panther movies combined with Smithers from The Simpsons (with Napoleon being his Mr. Burns).
While Napoleon himself was apparently fond enough of Chauvin to reward his devotion with a small pension, everyone else saw him as a ridiculous ass-clown who took the whole "patriotism" thing way too far. After Napoleon's fall, Chauvin's name became a synonym for anyone who was extremely patriotic to the point of stupidity. Entire plays and books were written about the poor idiot -- how much of his life really happened and how much came from those stories is up for debate.
This roughly translates to "Chauvin the Shitheaded."
A century and a half later, the word "chauvinist" was adopted by 1960s feminists looking for a better way to describe men who are irrationally convinced of their own superiority, because sometimes "Nazi" just doesn't cut it. The new meaning soon overshadowed the old one, but what hasn't changed is that Chauvin is still a moron.