Because we know that some students train in French and then want to take the exam in French. In the meantime, however, they have to use preparatory material in English. So they take their university training in French, they have access to a range of resources that exist in English but not in French, and then they choose to take the exam in French.
In our investigation report, we published statistics on the number of students who have studied in French but chose to take the exam in English. As we said, this undermines the vitality of the French language, and that shouldn't happen.