As a frequent Berlin flyer - as recently as about 2 weeks ago flying ATL/CDG/TXL, you will ABSOLUTELY have to go thru EC immigration.

First of all, of all the times I have done this, I have NEVER encountered immigration lines like I did this time. I arrived on the first flight of the day around 6AM, and even in the SkyPriority Acces No1 line, I waited 1 hour an 15 minutes!!! People were SCREAMING (I kid you not) at the officials because (surely more than 100) wheel chair pax and UMs were skooted ahead of us and only 1 SkyPriority window was open! The NON SkyPriority line filled the entire room and was COMPLETE MADNESS!

In a perfect world, DL should be able to check your bags through, and 1:40 should be plenty of time, but, consider that typical intra-Europe cheapie tickets are completely NON-changeable! If you miss the flight to Berlin due to DL, or even immigration lines, AF is under NO obligation to rebook you on the next flight - - PARTICULARLY AF's new "Mini Fares" which are highly restricted!