You can only use 2 days of your pass to travel in your country of Residence Germany This means you have to pay for atleast on of the 3 days that have routes in Germany personally i would go from Karlsruhe via Appenweier to Strasbourg (on my own with a regionalticket or the 49€ ticket) and catch the TGV to Bordeaux from Strasbourg as the route Karlsruhe - Strasbourg will be the cheapeast one :) 

Thanks that helps. I found a connection that will bring me till Strasbourg on my first travel day.

The rule is that you can travel on up to any 2 days of your pass in your COR (Country of residence).On these days you can travel on as many trains as you wish in your COR or any of the other participating countries. There is no requirement to leave your COR on these days.

There is an ongoing trial of some passes receiving an extra day but this will be shown in your pass.

Note travelling on any train that has a scheduled stop in your COR but you do not leave the train will still trigger a COR. e.g. Paris to Amsterdam on Eurostar Thalys passes through Brussels and Germany so would trigger a COR day for Belgians and Germans.

Paris to Amsterdam doesn't go through Germany. :)

Actually doing Paris - Amsterdam doesn't trigger an inbound/outbound day for Belgium.

A French traveller asked whether he could do Brussels - London without using one of these days (even though the train stops in Lille) and customer support allowed it. Let me find the thread.

Actually it does. I just tested this.

Only if there's no scheduled stop in your country of residence, the app will not detect that you're travelling through your COR and therefore won't use use an inbound/outbound day. I'm not sure though if this is intentional or just a lucky coincidence.

Is that a new behaviour then? I thought the Lille stop didn't trigger it.

It's no new behaviour as far as I'm aware. I only recall a story about a French resident on a Eurostar from London to Belgium that did not stop at Lille and therefore did not trigger and inbound/outbound.

The search function here however is suboptimal, to put it mildly, so good luck finding something...

You're right : I remember wrong. Indeed, impossible to find that post...