Upvote:1
This should be possible using only return tickets, buy yourself a return ticket from CDG to FRA, leaving on D and returning on D+1. Then buy a return ticket for your wife, leaving on D+13 and returning on D+14. Your child can then have a ticket leaving on D and returning on D+14. With you/your wife being on a different booking it is unlike you will be seated together, you could try and ask if someone would be willing to swap or pay to choose your seats.