Ugh, I really sent myself down a red herring on this one..
33 has another meaning that fits PERFECTLY with this book.. I'll spoiler tag it in case anyone is also chasing this path, but it's NOT the right answer..
Spoiler!
The eiffel Tower was first opened on March 31, 1889... 3+3+1+1+8+8+- = 33... Ugh!