Steven and Hans-Karl just mentioned the possible sources ... here's the content of them:
The article in the german "Zeitschrift für Heereskunde", no. 9, 1929 gives the following:
Black pole with brass tip; the fanion had the regimental colour on top, the triangle beneath was green (fusiliers) or light blue (grenadiers); on the middle of the fanion a black sign, surrounded with red, bearing the yellow company number (grenadiers a black grenade instead of this company sign); the fanion was mostly carried by the sappers.
A part of the stated picture by Hess (Battle of Wörgl 1809) is shown beneath.
Nice regards from Germany