Peter Auto has become the first major European promoter of historic racing to announce calendar changes due to the spread of coronavirus.
The French organisation has postponed both major events it had planned for April but hopes to run them later in the season.
The Dix Milles Tours du Castellet race meeting at Paul Ricard originally scheduled for April 4-5 has been put back to July 25-26, while Tour Auto Optic is now scheduled for early September.
The Paul Ricard race meeting was due to be the opening event of the Peter Auto season, including the first races of the season for Group C, Classic Endurance Racing and the 2.0L Cup for early Porsche 911s.
It is now scheduled for the weekend of July 25/26, a week before the Silverstone Classic in the busy summer schedule of historic racing festivals.
Founder Patrick Peter said: "With just a few weeks to go to the Dix Mille Tours we share the deep disappointment of all the fans who were really looking forward to this event as well as that of the drivers and our partners."
Meanwhile, the classic race and rally Tour Auto Optic 2000 has been moved from late April and will now run across France from August 31 to September 5.
The route remains unchanged but it will now clash with the Zandvoort Historic Grand Prix.
Peter said: "The adventure of the Tour Auto Optic 2000 is nothing without all the people who put their trust in us - drivers, partners, spectators and also all our volunteers.
Thus, the postponement of this great event became unavoidable to allow us to live our passion again in complete safety in September."