My vote: Charles X
Seriously, how fucking stupid do you have to be to think that little thing called "the French Revolution" was of no consequences and that you could act as if it never happened?
In regards to the others:
Henri I - Eh... I'm not so sure. I don't really remember anything great he did, but at the same time I can't really think about a true failure... Then again, he's basically one of the few kings of France we don't give much of a fuck about...
Louis VII - Kinda harsh considering that the only thing he failed in are basically his marriage to Eleanor of Aquitaine and the Second Crusade... Sure, these failures are pretty big, but he also did a number of important reforms: he strengthened royal power and he began centralizing the administration. The awesome man that was his son Philippe Augustus basically expanded on some of the reforms his father had done. Not to say Philippe Augustus is overrated, just saying his father gave him a strong basis to start that he use extremly effectively.
Philip IV the Fair - Why is he even on that list? You're calling the third best king of the Direct Capetians as one of the lamest? Why? Because his succession was a mess? Not his fault all his sons died in a such a quick succession without male heirs! Hell, if anything, that's just bad luck!
Philip VI the Fortunate - Bad King? Definitely given that he rather poorly handled the beginning of the Hundred Years War. Wort of the bunch? Eh... He kinda has a few circumstances... I mean, the Black Plague started hitting France while he ruled. Plus it's not like the whole mess with England happened overnight and had no past causes like the historical Plantagenêt-Capetian rivalry...
John II the Good - Yep, losing a major battle and getting captured really doesn't help your rule, especially when your ransom nearly bankrupts your kingdom and forces your heir to basically create a new money. Still, I'm not sure he's the worst in the bunch... I can at least name his bravery in battle as a quality even if it's not much.
Charles VI the Beloved, the Mad - Definitely not a great king but at the same time he was mad and that basically meant he could only rule in name... So, really, the failures of his reign aren't his fault. Unless you want to blame him for becoming mad, but that's just petty.
Charles IX - A king that was too young in a fucked up period of time. His reign isn't one of the shining period of French history (especially thanks to St. Bartholomew) but I don't think he alone should be blamed. Granted, he still did pretty badly but frankly given the situation and the entourage he had, I think a good deal of other rulers would have failed as badly...
Louis XV - I'd rather rank him as mediocre than as a bad king. He did rather poorly but he was still at the head of the strongest european power during his reign and culture was rather flourishing. Plus, given he was rather depressive, I have a tendency to sympathise for the guy...
Louis XVI - You can basically sum the guy up as "Wrong King at the Wrong Time". A (too) good natured man, willing to reform but lacking the authority and strength needed, and the whole mess he had to face was basically something he inherited from his predecessors. Add to it that the French Revolution was a rather complicated thing to handle, the fact he was rather ill prepared to rule (because his father and grandfather kinda ignored to prepare him for the job) and that he wasn't in the best mental disposition at the time and it's only natural he failed.
Louis-Philippe Ier - Eeeh... Considering who came before him, it's hard to say he was the worst. Not to mention that he kinda succeeded in some places. The July Monarchy's a bit of a transitionnal period but it wasn't that bad...
Napoleon III - As far as I'm concerned, he doesn't really have his place here. He was rather awful at foreign policies but he did rather well domestic-wise. The Second Empire is actually a rather good period for France in terms of economic growth and industrialization. There are also a few worker's right policies that he put into places because he had a genuine care for their conditions. Sure, it all ended badly in the Franco-Prussian war but considering you have the magnificent bastard that is Otto von Bismarck on the Prussian side...
Louis XIV for setting up Versailles and spending way to much on wars for too little gain.
That's kinda forgetting all the important reforms Louis XIV did in his reign, how much France extended its borders thanks to him (even if the wars in the end were disastrous for the economy) and the fact France reached its peak in power during his rule. Sure, the Sun King is a bit overrated, but he still deserves his place among the great kings of France.