En route to Elba in April 1814, Napoleon wore a Russian General’s greatcoat now in the Army Museum Vienna.https://twitter.com/HGM_Wien/status/1253941975562227712?s=20 more on the blog if you read German.
Let's see if it works now, the coat of FML von Koller which Boney did wear to disguise himself from the French people.
For those able to read German, another story on a coat with a russian connection. Although not a great coat.
https://von-bastille-bis-waterloo.wikia.org/de/wiki/Den_Haag#Von_Reisende.
Down where you see the russian flag, they discuss.