French Open organisers estimate up to 60% of the usual capacity will be allowed inside Roland Garros when the rescheduled event is held in September.
A maximum of four people will be able to sit together on the main courts with an empty seat between groups.
On the other courts, one seat out of two will be empty when the main tournament starts on 27 September.
The US Open is being held without any spectators in attendance in New York from 31 August to 13 September.
Wimbledon was cancelled this year for the first time since World War Two because of the coronavirus pandemic.