Is it possible to fly non-stop from the U.S. to Marseille, France?
Not anymore. At one time I believe Air France had flights from JFK.
Walter,
I'm not thoroughly familiar with the flight options from your area, but I doubt there would be a non-stop to Marseille as there's probably not enough demand.
You'll probably find that at least two flights will be involved, with changes either in Paris or Frankfurt.
Cheers!
No, but from Houston you can do it with one hop in Amsterdam, on KLM.