You need a global pass and you can't use the metro with an Interrail pass. 

Depending on when you plan to travel it can be cheaper to buy normal Supersparpreis Europa tickets at Deutsche Bahn than an Interrail pass plus reservation if you want to travel with the high speed trains to France. 

A global pass has a minimum of 4 travel days.

Thank you for the quick reply. I am planning to go in a few weeks and the prices at Deutsche Bahn are very expensive at the moment. But ok, I keep my eyes on the Supersparpreis Europa tickets Thank you!

When do you plan going? Where do you leave from in Germany? 

You might want to check out the Carte Acantage from SNCF. Now for 25 euro, instead of 50. Tt can cut ordinary ticket prices very sharply (30% off and maximum prices) .

 If you state the days and departure date I can look it up for you how much you can save with the Carte Avantage. 

Hey thanks for your offer. :) 

I plan to go from Stuttgart to Paris on December 9th at 1 or 2 pm and return on December 11th around 5 or 6 pm. 

I can find something for 175 EUR on your +/- requested times. I've seen cheaper. Screenshots below, unfortunately only in Dutch. You might be able to find much cheaper if you tale the last train on friday, and take a train on monday 12th should that be an option. Interrail would cost you more and needs additional reservations. 

So the carte Avantage would save you a bit, but not a lot. If interested, you can find it here https://www.sncf-connect.com/app/en-en/catalogue/description/carte-avantage-adulte.

(I've seen the Carte slash prices by half on some occasions, so the offer above is a bit meagre. But now it's only 25 euro, so if you plan other trips to France the next 12 months, it's going to be a good deal.) 

Hey Brendan,

thank you so much for your time and effort! Since there are only very few seats left on those trains and since I am not planning more trips to france this year, I just went the quick way and booked without the card. As you said, sadly it doesn’t save a lot in my case. 

This is very good to know for future trips tho! :) 

Have a nice evening! 

No problem, you're welcome. Have a nice time in Paris! 

Also dann jetzt zu spät: sehr oft ist es für eine Reise wie hier billiger mit NV/B-W bis Kehl+Zuschlag Strasbourg zu fahrne und dann gesondert TGV in FR-SNCF zu buchen-jede Stunde.

Aber genau für diese straff im Wo-end eingepasste Wunsche sind sehr viel mehr mit gleciher Plan da-das ist nie billig.

You want to travel on a Friday afternoon and on a Sunday evening, which are busy times so you will have to pay a lot unless you can change your travel plans and leave on Thursday and return on Monday. There is an evening train on the 8th that will take you to Paris for less than 55 EUR and an early morning train on the 12th that will get you to Stuttgart for less than 45 EUR.