Translation from a dutch website..:
When: Formula 1 visited Clermont-Ferrand four times: in 1965, 1969, 1970 and 1972.
Special: The eight-kilometer course was almost three times as short as the old Nürburgring, but at least as spectacular and fast. At the end of the fifties the circuit was composed of existing public roads that meandered through the volcanic hills at Clermont-Ferrand. They turned out to be beautiful racing roads that did not give the drivers a moment's rest. One corner followed the other, there were almost no straight sections. In 1969, some drivers even opted for an open helmet, rather than a closed one: they were afraid that they would go over their necks due to motion sickness.
Memorable: The soil in the region around the city of Clermont-Ferrand consists of black volcanic rock. Pieces of razor-sharp material constantly broke off the mountain walls next to the circuit and ended up on the asphalt. During the Grand Prix in 1972 no fewer than ten drivers drove a tire flat on a piece of rock. Among them, eternal bad luck Chris Amon, who missed out on a certain victory for the umpteenth time. But it could be worse. During the same race, a stone raised by the car of Emerson Fittipaldi, the visor of the Austrian Helmut Marko - pierced the current talent scout of Red Bull Racing. Marko lost an eye.
The stone bombing ensured that Formula 1 no longer returned to Clermont-Ferrand. The circuit was also too dangerous in another respect: there was no room for run-off lanes anywhere along the track. The royal class relocated the years after 1972 to Dijon and Le Castellet, specially built racing circuits that were a lot safer.
(but a lot more boring) Well should be fun...