Transit Visa requirements are enforced indiscriminately...
StillAlive,
I believe that TV requirements and enforcement differ even within one country's borders. For eg, the french consulate website clearly states that "IF" you have an Advance Parole and no other valid Visa to return to the US, you will "require" a transit visa.
Now, if you are not deboarding in Paris at all, and not going through one gate to another, I can see why there will be no check required of your TV. My visa was looked at, but no stamp etc was marked on the passport even though I deboarded and went through a good ten minute drive to get to another gate (Charles De Galle is a huge airport).
On the way back, because of a flight cancellation, Airport officials had to stamp a 24 hour tourist visa as I had to leave the airport to go to a hotel for the night.
In any case, it is best to follow the requirements posted on the intermediate country's website so as to stay on the right side of the law, if ever things came to a pass. Just my two cents.