Originally Posted by
Palal
If you enter the Schengen zone and walk to the FCT, then you'll get:
1. Entry stamp at FRA
2. Exit stamp at FRA
3. Entry stamp in LHR
4. Entry stamp in BCN
5. Exit stamp in your exit Schengen airport.
FRA usually stamps foreign non-residents, LHR always stamps, BCN always stamps (in my experience).
If BCN is similar to MAD, you may want to watch where they stamp. Exiting MAD, the Spanish passport control officer just stamped the inside of the back cover of our passports.