Upvote:1
You can write a note that you're going to take the train to cross from Netherlands to France and submit it along with the rest of documentation, so they're confident that you did think of that.
I was adviced to do just that at visa center and did, with success.
Upvote:2
There are many ways to travel from Paris to Amsterdam and for many of those you do not need to buy tickets in advance.
Visa officials know and do understand that.
If you prefer to show a ticket/reservation, look into bus travel. If booked early they can cost as little as β¬15.