Someone called Coast to Coast last night and floored Steve Hagman and George Noory with the same scenario. Saying that it didnt make sense not to hit the crowds around Live8, where a lot more casualties would have resulted, and that France was likely behind the attack.
They didnt know what to say for a while.
You could plan the attack to happen "the day after the announcement" Look at how much integration the French had with Iraq, and the old Saddam regime.
Interesting theory about the French. I suppose it's possible, but the idea is a little out there IMO. I am of the belief that AQ likely has cells in certain cities (especially in Europe - probably including France) that are basically ready to go at a moment's notice. Survaillance of the transportation system is probably the easiest of all targets, just riding the train daily would keep whoever is interested in attacking it up to date with what goes on.