It was a common event for a newly occupied town to catch fire. Albrecht Adam recorded one such event that happened on the 18th of July, 1812.
“We set off for Dokzice, a march of 21 miles being necessary to reach that place. The town is inhabited almost exclusively by Jews. it has an attractive central square, a church and a miserable mansion house constructed of wood. The outskirts of the town are built on two heights with a little marshy stream running through the middle. On the day we actually spent in the town the Viceroy [Prince Eugène de Beauharnais] was accommodated in the mansion house. A small plume of smoke was spied rising from just behind this place, quickly followed by flames. Soon the fire was consuming the neighbouring houses but, fortunately, the army rushed to our assistance and our fears vanished when the fire subsided.”
With Napoleon in Russia: The Illustrated Memoirs of Albrecht Adam, 1812; Edited by Jonathan North