I assume that this was on a flight arriving at CDG.
It is surprising that she did not inquire about her missing bag at the baggage service office when she arrived. They would have automatically asked her to fill a report.
Maybe she did not realize that the bag was missing and left the airport.

It could well be that the bag is simply sitting there.
It is also surprising that Air China does not respond to her phone request.
As suggested below, you should truly insist with the airline by phone. Going to the airport seems a hard way way to do it, and a week is a long time to try to locate a bag.
https://easycdg.com/delayed-lost-mis...s-cdg-airport/