Gentlemen;
One of the absolute best sites on the subject of French flags, pre- and post-1789, is here:
drapeaux.org/Accueil.htm
This is Arnaud Bunel's "Vexilollogie Militaire" site. My link takes you to the title page (all in French) where you scroll down and click "France", then click "Ancien Regime" if you are looking for pre-1789, then click "Infanterie" for the various infantry regiments, then "Infanterie de Ligne". The first list it brings up is regiments AS OF 1789 and their flags at that time; although it also shows their lineage and previous known flags as well.
Note: The sections on the Maison du Roi are very incomplete, only the Infantry has much.
A good example is the Irish regiment Dillon, the lineage is shown dating back to the pre-1690 English regiment Shrewsbury, then Regiment de Dillon and so on. All of the known variations of the flags are given with the dates for each. You can use these illustrations as a painting guide, or right-click and copy, then past into Paint or similar to get digital artwork. You will have to do some clean-up on the art in Paint, but can get very respectable flags.
Next up; Tom Gregg's "War Flags" site. It is not as complete as Arnaud's site, but it is in English, and offers a good overview of the "rules" of French policy governing flags, who carried what, why, etc.
tmg110.tripod.com/royfr4.htm
If you want to view Tom's complete collection of Ancient France, use this link, then select the specific category you want to see (i.e.: Irish Regiments, Swiss Regiments, etc.)
tmg110.tripod.com/france1.htm
Hope this helps. BTW, John is right, you should have "fum" with this project; I think it is one of those Yankee beers ;-)
Bill