<i>Prince du Sang Royal</i> crown, attributed to the sons of the King of France (save the first) after <a href="https://en.wikipedia.org/wiki/Francis_I_of_France" class="extiw" title="en:Francis I of France">Francis I of France</a>. Before that, it used to be the royal crown of France.
Tomasz Steifer, Gdansk
CC BY 2.5
<span class="int-own-work" lang="en">Own work</span>