"In Rome, a freed slave had his head shaved. Then, they would wear a pileus, in part to keep their head warm. The hat was a sign of the slave’s freedom/liberty.

Somewhere along the line in the French Revolution, they adopted the freed slaves’ head gear as their own symbol of freedom, but picked the wrong one."

Fun fact: You can see a pileus on the Ides of March coin reverse from 43 BC, minted by Brutus to commemorate the assassination of Julius Caesar in 44 BC.

https://en.wikipedia.org/wiki/Ides_of_March_coin

People have been using silly hats for political purposes for millennia.