President Jacques Chirac on Friday ordered an investigation into a retired French professor who spoke at this week's conference in Iran of Holocaust deniers from around the world. Chirac ordered Justice Minister Pascal Clement to "carry out a thorough preliminary investigation" into statements by Robert Faurisson at a press conference in Teheran, the president's office said. Clement then ordered Paris prosecutors to launch the probe to determine whether Faurisson's statements can be prosecuted under a 1990 French law making it a crime to deny the Holocaust. The law would apply if the statements were published on the Internet or in a newspaper distributed in France. Faurisson has been convicted five times in France for denying crimes against humanity. Last month he was fined for denying in an interview with the Iranian TV channel Sahar 1 that the Nazis meant to exterminate Jews. Faurisson has claimed that no gas chambers were used in World War II Nazi concentration camps. Iran drew worldwide condemnation for hosting 67 participants from 30 countries at a conference debating whether the World War II genocide of 6 million Jews took place.