What Happens at the Chateau in France?

Elise comes to Diane's apartment with the second copy of the videotape and then they take her with a hood on to a chateau in the countryside. Later she is brought back asleep to her apartment after having been injected. What do you think happened at the chateau? What was that all about?

Also did Diane think her fight with Gina was all a dream until she saw the video?

There might not be answers to these and other questions, but just curious what people think.