Travel from Delft to Paris

There is only one option if you want to take the train from the Netherlands to Paris; the highspeed Eurostar. From Delft you first need to take a local train to Rotterdam. In Rotterdam you then transfer to the Eurostar to Paris. If you book this on the international website of the Dutch national railway company NS you can book this as one ticket https://www.nsinternational.com/

You can book this in the SNCF app on your phone.

Depending on your passenger category and discount/loyalty codes, it can cost from around §100 to 150 and you arrive in Gare du Nord in about 3 hours. Better pricing if you do it ahead or remembered to renew your discount card this summer. [Oops.]

Note that if you have time to eat before your Eurostar departs from Rotterdam there is a great trattoria that will ease your transition from Dutch 'hospitality' as evinced above and the warmth of southern Europe.

https://trattoria-a-proposito.wheree.com

Pricing seems to be slightly cheaper using SNCF than the Dutch website, and to my romantic ear, a bit easier to understand.

Please note that the reason that the prices on the website of the French railway company SNCF are slightly cheaper for the journey from Delft to Rotterdam is that the SNCF can only sell you the Eurostar ticket from Rotterdam to Paris. It can’t sell you the domestic portion of this journey; Delft to Rotterdam. Which means that you would need to buy an additional ticket. NS International can sell you a ticket for the whole journey from Delft to Paris.
In addition to that, the SNCF discount card, is not valid for the Eurostar. It’s valid on the highspeed train TGV, but that train doesn’t go to and from the Netherlands.
If bought well in advance, the price for a single ticket from Delft to Rotterdam can be as low as €39.

Good to know, thank you DT

SNCF has decided it cannot be bothered selling tickets to places that do not have direct trains from Paris.

So when buying tickets from some country to France, or from France to some other country you are always best of using that other countries national railway.
So tickets between France and the Netherlands you best buy on https://www.nsinternational.com/, and that in both directions.

Indeed, much better to purchase the ticket on the Dutch website as noted by Dutch Traveler and Wengen.