Organisers of the French grand prix are seeking a contract extension.
This year, Paul Ricard meant that after a ten-year absence, France returned to the F1 calendar.
The current contract is for five years.
At this year's event there were notable traffic problems, but promoter Christian Estrosi said the issue can only be sustainably fixed if the race's future is secure.
"Before we discuss road infrastructure, we need to ensure a sustainable presence," Auto Hebdo quotes him as saying.
"We need a longer secure period and are discussing a contract of 8 to 10 years. We cannot build highways for the 2019 season," he added.
But Estrosi said that from a financial point of view, he is happy with the results of the 2018 race.
"The EUR 68 million of revenue we wanted was achieved so the return on investment has been successful," he said.
