The AirFrance site says economy ticket flights on NW earn 100% of mileage for FlyingBlue, EXCEPT class V which earns 25%. (Higher % for elites)

Hope this link works:

http://www.airfrance.us/X04/en/local...cekedgfndghk.0

But read that fine print and listen to those other posters! I don't personally have any direct experience with Flying Blue (and clearly didn't read your question well the first time - sorry).

Romelle