[4] Though the House of Arenberg had long aligned itself with the Austrian army,[1] Prince Auguste's maternal grandfather, Louis Engelbert, offered his regiment in the French service to Prince Auguste since he did not have a son; it was further arranged that he would take on the title Count of La Marck following his grandfather's death.

[5] The Duke requested permission from Queen Maria Theresa for Prince Auguste to join the French service, which she granted.

[1] Upon his return to Paris, he was involved in a duel with Karl Peyron (1757-1784), a young former Swedish officer from his regiment who had led a revolt after he found out he was being shipped to India as opposed to North America which he favored.

[citation needed] He left the military in 1789 to join the court, where he remained largely apolitical and did not seek the monarch's levée or the minister's ante-chamber.

However, he lost command of his regiment by the National Assembly and he eventually left France, choosing instead to join the Austrian army as major-general.

[citation needed] Prince Auguste attempted to return to France after his brother became a senator and count in the First French Empire but was prevented from doing so by Napoleon.