[2] In 1812, Edmond also received a regiment in Brescia (north Italy) from Talleyrand, and on 19 September 1813 was promoted to oberst.

He served in the War of the Sixth Coalition, commanding three Chasseur regiments under major-general Leopold Wilhelm von Dobschütz (1763–1836) at the battle of Mühlberg in 1813, where he was captured.

Thus, at the Congress of Erfurt in 1808, he approached Tsar Alexander I of Russia for permission for a marriage between Edmond and Dorothea von Biron, as a reward for Talleyrand's diplomatic services.

Talleyrand was certain of gaining permission from the bride's mother, since he was on friendly terms with her and since payment of her annual apanage was dependent on Russia.

[2] Edmond and his wife had children, but by 1812 their married life was over, with Dorothea having become his uncle's lover and (after his death in 1838) his sole heir.