This is a Eugenie’s actual gown in a museum today..

.. Designed by Worth who claims to have “invented” the crinoline, it is typical of just one of many Eugenie of France wore to affairs of state.

One might think this was white silk that had aged to yellow, but we know at this time in the Victorian Fashion Era, that white was specifically designated by Victoria to be for only wedding attire.  This most likely was indeed a pale shade of yellow for a ball or Court function.