I love period pieces, and I realize that I don't know any cinema that shows what life is like in between Roman Gaul and and early Captian France. Is there any media out there that's a good drama during the Merovingian regime?
I wish! After much hunting, all I could find was a pair of films about Dagobert. The first (1963) is an Italian/French comedy and the second (1984) seems little better for your interests.
The best list I could find of medieval movies is over at the Medieval Sourcebook. There are some Charlemagne movies in there, although I can't say I've seen any of them myself. A Taste of Cinema also has an interesting list worth looking through. For the older international films, I always recommend a Criterion edition, if you can find one.
For what it's worth, some of my favorite medieval or medieval-inspired movies include the following. Forgive me if some of these are a bit campy.
Of course there's lots of movies I haven't seen, and I know I'm missing some big names on this list (Name of the Rose, Lion in Winter, Flowers of St Francis, etc.). For Merovingian drama, I really think that Gregory of Tours is your guy. (Sorry that's an Amazon link, but it can be hard to find the right edition by Thorpe.) Gregory takes some getting used to, and the first few pages might be a bit slow for most modern tastes, but if you get to Book III it'll hard to put him down!