Ever since the Schengen treaty went into effect, I've had my passport stamped upon my first arrival in the zone. Until last month. Arriving at CDG on an AF flight from the US, we were not required to go through any kind of immigration check - just security before re-entering the departure area for our connecting flight. Upon our return to CDG from Africa, we were met at the end of the air bridge by French police, where our passports were checked, but there was no stamp provided, and the passports were not electronically screened.

Interesting that in the rest of the EU, the immigration checkpoint remains in operation.