Hauptmann von Blumenstein, billeted with Marwitz in Dresden in 1805 seems like quite the character. Although stereotypically French (lively, quick-witted and educated, angeblich), he maintained nonetheless that Blumenstein was his real name.
After leaving France (where he served in the Royal Musketeers) because of the revolution he becomes a dedicated Prussian officer, complete with, if Marwitz’s transcription is anything to go by, a rather curious accent.
When the French garrison he was besieging at Glogau in 1813 wanted to negotiate, he refused to speak in French and made them use an interpreter:
Ick bin ein Deutscher! Ick verstehe der verfluchten Kerlen ihre Sprake nick. Wollen sie mit einem Deutschen Offizieren reden, können Deutsch lernen! Müssen wir wohl Französisch lernen, wenn nach Frankreich kommen!
Later he retired to a small estate near Breslau where he apparently speculated unsuccessfully with a new type of brick(?), and ended up on his uppers.
Aus dem Nachlasse Friedrich August Ludwig’s von der Marwitz, Volume 1, Pages 138-139.