Just to try to keep your morale up, let me share some personal stories.
1. My niece family flew back from SFO on AF with 5 bags. One went missing and could not be located. She raised hell with AF up to top management. A week later, it was found in the trunk of the car (in California) that a friend used to take her to the airport. It was never checked in. This has become a family legend about her. (I know, she never had a tag for that suitcase).

2. I once checked 2 bags from Phuket to CDG on MH Fist class. One followed us, the other went to Osaka. It took 3 days to spot it there.

3. Once, we checked a golf bag plus 2 cases from SFO travelling AF F. The golf bag never made it and AF had no idea were it was.. After a week, I called the AF station manager at SFO (a friend of a friend of a friend) and he searched. It turned out that it was sent for custom inspection at SFO and returned in some weird holding area that no one ever checked.

4. Once, one of our bag was mistakenly picked up by another pax. Luckily he realized his mistake the next day. It was not easy to spot the extra bag that he left on the carrousel, as it was used for several arriving flights. It took 2 days for the airline to advise me, and another to be reunited.

All true stories, but my family always recovered all the bags in our 40 years travel history.
Hopefully, yours will be another amusing story to add. If you checked in at CDG (not a transit there) for RNS and one of your bag is still missing a week after the flight, that would be a bit strange though. I don't know how antique CDG systems are, but in many airports, the airline would know if your bag had been loaded on the flight.

Have you checked with the local police to find out if there has been such airport theft incidents? Have you files a police report?

Good luck.