I was poking about in some old files the other day and I unearthed this little gem, which may be of interest.
This is extracted from page 53 of `Napoleon und Erfurt aus Deutsche Quellen zum 22. Geburtstag Napoleons I 15.8. 1969.` Gesammelt von Irma List, Kopenhagen.

The Emperor stabs his Colonel.
Source: `Mittheilung des Vereins für die Geschichte und Altertumskunde von Erfurt`, Heft 22, Erfurt 1901.
By Bernhard Hoffmann, Marktstrasse 21.
`As I am now the only one who can deliver a fully authentic report of this event first hand, I feel that it is my duty to speak up, and promptly, as I am already 71 years old.
`During Napoleon`s visit to Erfurt from 25. - 28. April 1813, the following events took place. `My knowledge of these events comes from my father, the manufacturer, Wilhelm Hoffmann, who died in 1857, who witnessed what went on from really close up.
`He was then 23 years old and part-owner of the tobacco factory `Gebr. Hoffmann und Triebel` and a keen rider.
`He was watching a parade, which took place on the Schmidstedter-Feld.
`The Emperor had dismounted, in order to carry out a kit-check on a regiment of Marine Infantry (presumably the same one which fought so bravely at Möckern). `The men had to spread out the contents of their packs etc. before them.
`The Emperor examined everything very carefully and spoke in a very lively manner to the colonel, who was, naturally, also dismounted and standing beside him.
`When they were about opposite to my father`s location, so that although he could not hear what they were saying, he could see their facial expressions and hand gestures clearly, the Emperor turned to the colonel, with an angry expression on his face and clearly administered a sharp rebuke.
`The colonel responded also very robustly and my father had the impression that he was not respectful.
`Suddenly, the Emperor drew his sword and cut the colonel down. `As the colonel was carried away, the Emperor continued with his review.
`The colonel was carried into the Schmidtstetderstrasse, where he died in an inn.
`No-one dared to say anything to explain the event at the time, due to the numerous French spies, but they still talk about it now: the colonel was denounced by the Emperor for fraud, with objects that had been supplied to the colonel for the regiment for money.
`The Emperor had found his suspicions confirmed by his inspection, and - as the colonel had been insubordinate - he had stabbed him.
`It may be mentioned here, that the Emperor had been combatting fraud for years, as Malblanc wrote in his `Napoleon`; maybe the event at Erfurt was the drop that caused the cup to run over.`