It's probably not the best way to take the measure of French literary tastes, but based purely on the amount of times Balzac is referenced in any number of French films I've seen (most recently in Julian Schnabel's French production, The Diving Bell and the Butterfly), it seems clear that he's still very much revered there. (I looked, but nobody has felt compelled to compile a list of all the Balzac references running through French cinema--or at least hasn't seen fit to make it available online.) I suppose a case could be be made that he's one of a handful of 19th century writers of fiction whose works are still widely read and respected. Even cherished. In France at least. Elsewhere, one imagines he can be found on the occasional syllabus, read because he must, any pleasure derived by the student merely a happy coincidence.
I have a copy of Balzac's Cousin Bette on my shelf. I'm looking forward to reading it, hoping to catch a glimpse of what makes him so revered and hoping, as I suppose most of us hope when picking up a work of fiction, to be delighted and transported. He was, according to the books introduction, a bit of a coffee fiend, drinking cup after hot, black cup as he wrote through the wee small hours of the night. 4 to 5 novels a year! Prolifically caffeinated.