Well the lady was partly right... as of now when you make a reservation within Europe (which I am guessing would include Domestic Flights), you select a preference for seats (Aisle/Window) and then when OLCI opens you are automatically checked in a seat of your choice.
This is for all Voyageur tickets as far as I know.
See more below:
http://www.airfrance.fr/FR/fr/common...airfrance.htm?