Reservations are €29 in 2nd and €39 in 1st class, plus €2 booking fee per person if booked via Interrail.

Apparently, this bug still hasn't been solved. If you click further though to book, then the price will be corrected in the step before payment.

You can save money by using a TGV to Strasbourg or Mulhouse and then a fast regional train to Basel and any train to Zurich. For example:

If you're arriving in Paris by Eurostar, then Paris Est is just a short walk from Paris Nord. Reservations only needed between Paris and Strasbourg, book here:
https://travel.b-europe.com/Eurail-GE/en/booking-tgv#TravelWish

1st class €20.

Thanks for the clear information. I decided to go for it anyway (still cheaper than paying for the tickets outright) and was pleasantly surprised when the checkout page showed a much lower price of around £100 for 3 first class tickets. Still a lot for how interrail is advertised as being setup, but there you go, still a good deal for me.

To be clear for anyone booking TGV Lyria tickets via Interrail’s reservations: click through to the checkout and the price will be much lower (at least until this buf is fixed).

1st class price of these reservations was recently lowered from €68 to a slightly less excessive €39. Although you may find it a good deal, it's still SNCF using international passengers, and pass holders in particular, as cash cows.

@rvdborgt thanks for the update for the reservation prives of TGV Lyria

Yes it’s sad. It would be great if interrail was really as advertised, you buy a pass and travel freely and spontaneously. However the complexity as well as the cost of the reservations system makes trips less of a free flowing adventure than they could be.

Yeah there are really good and bad countries for Interailling.

You've got full flexibility and a great network in Germany, Switzerland, the UK, Belgium and the Netherlands

However Spain and France are pretty bad with a lot of (expensive) mandatory reservations, unfrequent trains,.. A lot of cross-border routes are bad too…

Italy is in between : mandatory reservations but the frequency is really good -> at least hourly but for example 4 high-speed trains per hour between Rome and Florence. Last-minute availability isn't an issue.