Yes, you need from the last station in Germany to France a reservation. You could try to call directly Deutsche Bahn or at Deutsche Bahn Ticket offices. 

The reservation for trips in france are managed in an other way, also when the train is from germany. And so is it possible that it works. 

Hi, I’ve called DB but they could not help me with this particular departure. It did not appear as normal within their system. When looking at other dates, it seems impossible to make this reservation for many dates in June/July. So I can’t manage to proceed here

Is it possible to use an other ICE or TGV for you? You could also try to get with regional trains to Strasbourg and then use ICE or TGV to Paris. You could check bahn.de for trains. 

Hi, and thanks. I’m aware of the options but I’ll be travelling with three tired kids and am looking for the most smooth solution It really bugs me that the train is there but still impossible to book. 

Is this the same question as the one below?

Hi! It’s related to the other one but a new question, the new one is: “do I need a reservation K-S”, which was not at all included in my previous post. The answers that I got here however advised me to follow steps that I’ve been trying before (as stated in my first question), which are not working out due to a problem that neither me nor DB understand or can overcome. Apparently also the staff of eurail.com are looking into the matter as it does seem strange that it can’t be booked