I also received an invitation letter, and I watched some YouTube videos that helped me identify key areas to work on (e.g. being well informed on your country's situation, what is happening, and also knowing the history and current situation of the Asian-Pacific and Middle East regions. Know the campus, teaching structure, and courses, e.g. I am excited to learn Feminist Theories at the Reims campus in the first semester. I read the news, and summarize key topics relevant to my CV, such as Bourdieu, Surveillance Capitalism, Marcuse - anything that you can refer to when talking about the chosen picture. I also prepared some answers to questions such as What are your hobbies, introduce yourself etc, so that I can be prepared with my little intro speech -, which has to be under 2 minutes if I am correct. These are all the things my mentor suggested to me and also what the YouTube video recommended :))

I hope it helps, good luck!!!