Math for Beginners

So TYM has a business trip in Paris next month, and naturally I'm tagging along. We've decided to hang out for a couple of days in Paris once he's done with all of his Important Big Tobacco Business, and then hop on the train and go elsewhere. I've been looking into flights to and from everywhere, and I've decided that airline pricing makes no sense whatsoever.

Riddle me this:
New York City to Paris (One-Way): $1,500
New York City to Paris, plus Geneva back to New York City: $535

The hell?