how to add eurail pass to b-europe site booking Paris-Lausanne/zermatt

What would you like to book ?

b-europe doesn't work for Interrail/Eurail reservations directly. You have to use this link for TGVs within France (to Strasbourg or Mulhouse on your itinerary) : https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish

I thought that you had already booked the TGV ?

Strasbourg/Mulhouse - Basel - Visp - Zermatt cannot be booked. Simply add the train to Rail Planner app before boarding, you get a QR-code which is your ticket and that's it :) You can sit wherever you want on the train. This is the same process for the vast majority of European trains.

So I've seen your other post :

I wouldn't recommend to cancel last-minute. Trains are almost full (if not full) so you surely won't all sit in the same carriage or even on the same train. The connection with 2 changes is by taking the TGV to Basel directly : it has an expensive seat reservation fee of 37€ 2nd class/70€ 1st class. That's why we advised you not to take it. Changing in Mulhouse will be fine and there are trains every 30 min onwards so it's not a big deal if you were to miss one (no seat reservations required at any point).