During the meeting with the 150 students, the school was told by a teacher of Islamic religion that Kichka’s account "was largely exaggerated".
"This never happened to me in 25 years", Kichka, who is regularly invited to meet young people, told Le Soir.
The school management had decided to film the meeting because, it said, "witnesses disappear and we want to keep tracks".
On Monday, the trade unions saw the video. "To us, there is no doubt, the teacher quoted negationist ideas from Roger Garaudy", a French revisionist author and philosopher who converted to Islam and called the Holocaust a "myth".
"This will not remain without effect", the school said. An administrative investigation has been opened."