cheap flight from paris to amsterdam

Take the Thalys high-speed train.

There are no cheap flights. As Tom says, take the train. When you factor in the time to get to and from airports, the train is faster than flying.

If you book well in advance (up to 90 days allowed) at www.thalys.com, you can get a Smoove fare as low as €35. There are a limited number of tickets for that fare so book ASAP. Choose "Paper ticket" and print it yourself. The standard 2nd class fare is €123 so it pays to book ahead.

Thank you so much. I can't book far ahead as it is for my boss and he is going in 2 weeks. He wants business class on the train if he goes. that way.

There is no business class on a train -- only first and second. The train would be much faster than a plane. Put him on the train.

The standard Comfort 1 (1st class) fare is €199. If you book ASAP, you may still be able to get an Optiway fare of €109.