Schels calls him wrongly Savary and gives him the rank of Lieutenant-Colonel of the Guard (equivalent to a chef de bataillon in the guard ?).
Saint-Denis was blockaded on 30th by the 15th Russian division under general Karnieloff/Karnielow, Savarin declined to surrender, and when he got to know on 31st about the capitulation of Paris, demanded to be included in it. This was denied and Savarin's troops (400 infantry, 200 National guard, 7 guns) were made prisoners:
https://books.google.de/books?id=gZ0dAQAAMAAJ&pg=PA254
Victoires, Conquêtes also states that Saint-Denis was merely blockaded, but mentions a failed attempt to bring ammunition there during the battle: