Upvote:4
The rule is that you will enter the Schengen area in Paris and will be free to leave and return to the airport. Your flight from Paris to Greece is an internal Schengen flight, effectively a domestic flight, with no systematic immigration controls.
If there is a passport check (either at random or because of emergency measures as noted in a comment), it will not create additional visa requirements. Such a passport check will not result in any stamps in your passport, because you will not be leaving or entering the Schengen area.