What are Napoleon's soldiers wearing on their heads?

I’ve been enjoying the British series of Sharpe TV movies starring Sean Bean and set in the time of the Napoleonic wars in the early 1800s. (The “still sharp” in-joke in LOTR led me there. I didn’t know of him before that.)

In many scenes of encounters with the French army, the French soldiers appear to be wearing bags on their heads.

I know what a shako is, and I’ve looked up French uniforms online and seen the shakos that were part of the uniform of the time. But I don’t see anything that looks like those bags. They appear to be wrapped around the shakos and remind me of a chef’s toque.

Do you know what kind of headgear is being depicted in the movies?