Originally Posted by
carnarvon
Indeed. I bought 2 biz class CDG/HAN under AF flight number and cannot select the seats.

Were you able to get the VN PNR by asking AF? In some cases, I have been unable to use the PNR to select seats online, but was able to select them by calling in to VN's call center. This was for a AF coded flight, FB redeemed like you did, but at least 5 years ago now.