Which expeditions of napoleon's proved disastrous to france and to his career?
the march to moscow in russia.
the expedition to egypt.
the campaign in italy against the austrians.
the battle in austerlitz against the austrians and russians.

Napoleon's expedition that proved disastrous to France AND to his career was: The march to Moscow in Russia.

Napoleon conducted this March because he knew that if His army managed to take down Moscow, French Empire will officially became the largest empire in the world. But the Russian army proved to be way too strong for Napoleon's army and most of the main forces of his army were annihilated.