flyerfirsts question is straightforward, and so should be the answer.
He contemplates getting a Y FB award with a transit in CDG. He asks if he will be protected if his flight to CDG is delayed.
The answer is a simple yes. AF will reroute him on the next available flight and provide right of care (food, hotel) if needed. Furthermore a possible compensation according to EC261 if that applies.

The possible question is what would be the next flight available. If the next flights are quite full, he will have a lower priority than other delayed pax with a paid fare or with status. But AF has been quite generous in arranging rerouting even on different airline.