What on earth are you babbling about?!?
There's nothing liberal or conservative this book. Nor would I consider the French to be 'liberal', within the American political definition of the word. The French are generally highly intelligent, well educated, progressive, but do suffer occassional bouts of paranoia, anti-Americanism, xenophobia, as do other Europeans from time to time.
As for being the number 1 bestseller in French all that proves is that a liar and a swindler in France can find as many gullible and ignorant fools as a charlatan in America promoting and selling stupid Moon hoax or Face on Mars theories.