I was going to cut and paste if it had been a short answer, but the debate as to who is first in line gets rather involved. I recommend reading the whole thing.
Now the claim to the French throne is a real mess. Bourbon, Orleans and Napoleonic contenders.
Nice little chart of the various vacant thrones here. And lest monarchists lose heart, many of us are old enough to remember when the Spanish throne was vacant.
http://en.wikipedia.org/wiki/Pretender
Interesting note - the same guy has claims to both Scotland and Barvaria.
But my favorite possible pretender {he has never pretended}is Ernst August of Hannover, Princess Caroline’s husband, because he is just SO ... Hanoverian. He is a direct descendant of George III and exhibits many of the “oddities” of earlier Hanoverians.
“Bourbon, Orleans and Napoleonic contenders.”
I would have to say the Valois have a much more ancient claim and thus more legitimate. Then the Bourbons. The Orleanist branch were a bunch of monarchist backstabbers and the Napoleonic pretenders are just that...pretenders.
Napoleon never had any royal blood, he was just a Corsican peasant who became a general, who was then coronated after the fickle French decided they wanted a ruler who wasn’t part of the messy and incompetent Directory. After Napoleon was exiled on Elba the Bonapartes should have renounced all claims and lived discreetly.
Of all, if I were to select anyone, I would have selected the Head of the House of Valois, or the Head of the House of Bourbon. They have the best claim at at each time the House ruled.
If neither were decent enough, then the House of Capet should be chosen. They were the first French monarchists before the Valois.