I actually finished the figures a while ago but couldn't decide what flag to use. Some French leaders certainly used swallow tailed standards - those of Gaston de Foix and Louis de la Tremoille as well as those used by royal guard gendarmes are recorded in contemporary pictures but I haven't been able to find any others. Instead (and thanks to Stuart M and Olicana for the information and advise) I just used his arms as a banner.
I found a suitably posed lion on the internet and printed off the outline of the flag about 1/2 inch high then overpainted it with my usual Vallejo paints to get a look that would be more consistent with the figure.
As with my Swiss and Landsknechts, the flag is mounted on brass tube which fits on a protruding steel core so it can be removed and swapped for a different flag if I want a different selection of generals or a different nationality.
I plan to do one more multi-purpose general and a Francis I to complete my French commanders.