The ATT phone mysteriously logged on to the Orange network, once I got near to Lyon.
Note that Orange was available in the other parts of France that I was in.
I can only conclude that either ATT tech support fixed a newtwork problem or that for some reason ATT will only work with Orange in some areas (Bytel and SFR also show up as available networks).
FYI: tech support said that manual network selection is not available on this model lazr-not what the network setting screen shows.