This has been stated for a long time :
https://www.interieur.gouv.fr/Actual...ational-travel
(Travel to/from a country outside the European area: 1) You wish to leave Metropolitan France)

You need either a compelling reason or returning to your country of residence/origin.
There are examples here or on other forums to pax being prevented from leaving when transiting from the European Area. Also examples where they were not.
The question is whether that is practically enforced. Whether it is legal is another issue.