Stuck for two days in Atlanta because of AirFrance
 

Because of AirFrance, I was stuck for two days at Atlanta airport on April 6-8, 2017. I could not even reach my final destination, Pittsburgh.
Because of the storms two days earlier, all air traffic was stopped. AirFrance knew it when they let me take my flight from Paris Charles de Gaulle to Atlanta on April 6, but they said nothing.
I arrived in Atlanta, and it was an incredible mess. I experienced many difficulties finding a hotel, which I had to pay myself.
I contacted AirFrance on April 9, immediately when I returned. After six weeks now, I heard absolutely nothing from them. This is a disastrous service, and it seems that for them their customers (even frequent flyers like me) count for nothing. Given this very bad service, I recommend to avoid AirFrance as much as possible.

Atlanta to Pittsburgh would have been operated by Delta, an Air France code share, Sky Team Alliance member. During the time there was some weather moving through so Delta is not obligated to put you into a hotel. You could have checked the weather channel before leaving France, and based on what was moving through re-arranged your travels.