Compiegne is the perfect complement to the Pierrefonds castle which is also related (through its restauration) to Napoleon III. It does make sense to include Compiegne in a 10-hour-full-day tour with Pierrefonds (or Chantilly or Ecouen) as they're all in the same area.

And, if it's your thing and if we go there quickly, we can also go visit the (replica of the) famous railroad wagon of the two world-wars which is only 15 mn drive from there (and I know a good price/value restaurant nearby!).

OR (interesting option here for our American friends):

Have you heard of the Franco-American Museum of Blérancourt? Not many people have...

I myself discovered it rather recently as it was under heavy restauration for several years and re-opened in 2017. Again, I would not put it at the top of my list but it's only half an hour drive from Compiegne and some of you can never hear enough of the Marquis de Lafayette so... And it would combine well with the wagon. But then we wouldn't have the time for a second chateau/palace in the afternoon... except if we do it on a 2-day-trip...

Anything is possible.

Just saying...