I am a poster with limited SkyTeam international experience. I had previously booked a DL flight into Paris CDG, arriving at 2pm from ATL. Due to unexpected business changes, I now need to go to Berlin. I found some same day, low priced Air France flights from CDG to TXL that I am considering.

Question 1- What is the minimum transfer time needed to go through immigration/customs at CDG and get to the gate for the TXL flight? I have two options: 3:40pm (1hr40min transfer or late that evening (~6 hr transfer), and would prefer the former if possible and practical.

Question 2- What issues should be expected buying two separate tickets in this fashion? If I bought both through Delta, would they be willing to check bags all the way through from ATL to TXL or not? (Doing carry-on only is a possibility if needed).

Thanks in advance!

you should not have to go through customs at all just security. However I am coming from another EC country so check this for sure.
However if I am correct 1:40 is plenty, CDG is a bit of a mess but that is plenty of time.
Would have thought also no issues with luggage going straight thru. with two tickets

I actually think you will need to clear immigration as CDG will be your entry point from outside the Schengen area. The CDG-TXL flight will basically be the equivalent of a domestic flight.

All that said, even clearing immigrations and security, 1:40 should be plenty at CDG. Although there are no guarantees on a split ticket, if your arrival from ATL is delayed such that you miss your onward flight, there is a reasonable chance that AF will still place you on the evening flight to TXL. Things like that are one of the actual strong parts of the DL/AF/KL partnerships in general (can't say the same for rest of SkyTeam).

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!

Another consideration - - -

If the CDG/TXL fare you're considering is an AF "Mini Fare", baggage fees are NOT included. You may be asked to pay the baggage fees when you go to get to a transfer desk at CDG to get your boarding pass.

I have been asked a couple of times to pay baggage fees mid-trip at CDG til they verified my SkyTeam Elite + status - - even on this past trip when I checked a bag from Chicago ORD all the way thru to TXL, and my trips are never on AF Mini Fares. They have always been on Delta ticketed itineraries starting in the USA.

Saw the exact same situation on 3/3, not sure if you flew on the same date. First time I've ever seen the line that long, and the immigration line so chaotic. But this is definitely not the rule at CDG.

An even further consideration: Avoid OLCI for the domestic segment before getting the airport tagged to the final destination. Last year, I was traveling on 2 separate tickets and did OLCI for the intra-schengen flight before heading to the airport. No one was able to check my luggage all the way through and didn't seem to figure out what the problem was. A supervisor ended up calling technical support, who unchecked me, and was able to issue the bag tag all the way to the final destination. They also printed the BP for the connecting flight, so I didn't have to stop at the transfer desk.

Just checked my date - - I went thru CDG on Feb 25. I've never taken a flight that arrived at CDG so early - DL82 which arrives around 6AM, so it seemed like a ton of other international flights arrived around the same time from non-US destinations. I'll surely do my best to NOT transit CDG that early in the future!

Just a side note - - I took that very early arrival to spend a half day in Paris before going onto Berlin. I had a 9 hour layover. Took a shower and had a quickie mini-breakfast the the AF Long-Haul Arrivals Lounge. I arrived at 5:50AM, but with all of the EC immigration hoopla, I didn't get to the RER-B train til around 9:30. It was nuts!

Thank you, the information is all very much appreciated. Based on the advice so far, I think I will probably roll the dice and try for the shorter layover.

Good luck, and DO let us know how it all works out!