INFORMATION : 
From 22/3 starting 11.30pm: flights operated from Paris-CDG Terminal 3 & 2G are reassigned to others terminal.
From March 26th at 11:30pm, flights operated from Paris-Orly 1,2 & 4 are reassigned to Orly 3.
From March 31th at 11:30pm, until further notice, flights operated from Paris-Orly are reassigned to Paris-CDG.
  Find more

Due to the current situation regarding the epidemic of the Coronavirus Covid-19, traffic is reduced on the RER B (Find more). Orlyval service is suspended from March 27 at 21:00 until further notice. The Bus Direct traffic is also modified (Find more).

Special travel certificate: the French government has taken measures to restrict mobility. Each person wishing to travelling will have to hold a document certifying the reason for his or her displacement. 
  Find more on the French government

Warning: access to the terminals of Paris airports is restricted to employees and passengers (with a reservation) who travel only in the context of the exceptions provided for. Taxis and transport are always available for these journeys.