For what it's worth: everyone travelling to the Games (specifically athletes and staff, of course) will have to depart from a pre-accepted 'hub'. So far, those are only Paris, Hong Kong, Tokyo and Singapore, and entry into China can only be via Beijing.
Meaning every single athlete and coach will have a direct Paris - Beijing, Hong Kong - Beijing, Singapore - Beijing or Tokyo - Beijing flight, any other departure location is not possible so far.
Two negative tests are needed, one 96 hours before departure and one max 72 hours before departure, it must be done in a laboratory 'accredited by China'.