Originally Posted by
novicetraveller
on the way back from CDG to FRA does one clear
immigration, customs and security at CDG or if it what happens where?
regads
You don't go through anything then, since you travel between Schengen+EU countries. No Customs, no immigration. Only security as usual on every airport.
It's like a domestic flight in the US.
Once you entered the Schengen area, you are free to travel between those countries without any immigration procedures. You will go through immigration at the airport where you are about to leave the Schengen area, FRA in your case.
Greetings from Germany