It's okay. It's a 3 star book. Our heroine, Madame Labert is the young wife (teenage bride, now with a few years beneath her corset) of a famous French magician, Henri Lambert. She's not happy in her marriage to a very wierd and much older man. You get lots of glimpses of bored/sad/frustrated housewifery a la 19th century. Boring house parties, utterly dull audiences with Napoleon III. There's a dark threatening Colonel orchestrating everything. There are scary Algerians and wise Algerians and all too human Algerians and I confess - I never read the part about Algeria. I just read the ending and it left me completely unsatisfied so I didn't bother to take the train to the last page.
Based on a true (ish) story.
And what do you know - it's going to be a movie!
Some websites if you are curious: