Not sure whether to fly or take the rail.
If by rail, it is 10 hours at least by train. Strasbourg would just about be half way if you want to take a few days to do it.
Edit - I see that Deutsche Bahn will let you do up to a 24 hour stop over in Strasbourg and still hold the 69.90 EUR price.
Easyjet flies direct from Berlin-Schoenefeld to Lyon with prices comparable to rail. I'd prefer that. Make sure you check the luggage regulations carefully.
If you prefer not to fly, there is a rail route , which I would use as I travel solo.
Take the night train Berlin Hbf to Offenburg, take the S-Bahn over to Strasbourg, then the TGV Strasbourg to Lyon. No rush, very doable, have breakfast in Offenburg or Strasbourg.
Thanks to all for the quality advice.