Ahhh thank you! I've had three Skype interviews so far, and they've all been quite different and I've certainly improved after each one. Expect lots of questions about your research interests, writing sample, why that program, but also some standard job interview questions like "what are your strengths/weaknesses?" I honestly got some questions that I did not anticipate with some interesting perspectives on my research and my ideas, and just had to wing it...sometimes that worked, other times it didn't...
As for those of you wondering about whether the interviews are in English or French, prepare for both. For the most part, mine have been in English with 1 or 2 questions in French, so don't be surprised when a professor suddenly starts busting out some French at you! These kinds of questions though haven't been too intense; they've been really basic questions. They just wanna see how you sound/if you can actually speak French. Good luck y'all!!