Norberto Fontana, the former F1 driver, confessed in the Argentinian magazine 'Olé', that Jean Todt obliged him to block Jacques Villeneuve during the 1997 European GP. Todt requested this as Michael Schumacher was batteling with JV for the championship title.
(Fontana was part of the Sauber team, but Sauber was driving with Ferrari engines at that time.)
During the European GP at Jerez (1997), Jacques Villeneuve was only 0,822 seconds behind Michael Schumacher. As Schumacher was behind Fontana, the Argentinian got out of the way straight away, but didn't let Villeneuve overtake him. Fontana was in Villeneuve's way for 4 turns. After the 'incident', Villeneuve was 3,186 seconds behind Schumacher.
Now, Fontana confesses that he had blocked Villeneuve as requested by Jean Todt. Ferrari denies everything.
Schumacher didn't won the championship in 1997 as he deliberatly hit Villeneuve, but ended up in the sandbox himself.