Originally Posted by
Tifosi
There's a good chance I'm wrong about this, so hopefully someone either confirms or corrects me, but wouldn't you clear customs in FRA since that's the point that you enter the Schengen Zone, as you'll be disembarking an international flight to board an intra-Schengen flight?
You are wrong, but not too far off. You indeed clear
immigration at FRA.
You don't clear
customs until your final destination, which is BCN.