Le Comte de Monte Cristo. This is not an exact translation but is an adapted version for intermediate/advanced students. I found it an enjoyable and optimally challenging read back in high school.
Also, get yourself the French original and English translation(s) of most any article or short story in a subject matter that interests you, then – with a dictionary, at least at first – try your hand at translating it yourself and compare your result with the already-published one(s). I used this method to translate Montaigne, Descartes, even Proust, and it’s not as hard as you might think – I found it to be almost like playing a puzzle game. If you have a group that does this weekly with the same article and then meets to compare notes, it can be very helpful, plus you get into a lot of fun little linguistic debates.