I assume Hollande knew about this. The French will pretend to be upset, and the US will pretend that it has never happened. End of the story.
So let me rephrase it for you : France will pretend to be upset ... It's part of the game.
As a french, I just don't give a s US spying our officials, I'm much more worried any foreign secret service achieving it. It just shows how much our defense and digital security is weak. If I'm angry, it's towards our own services which can't prevent this kind of stuff.