AF and AS have interline agreements for tickets and bag checking. But that doesn't mean AF will check your bag through.
Originally Posted by
Merlinrnr
You clear US customs & immigration in YVR since it is a preclearance airport. So you will have to claim your bags in YVR and recheck them whether they are tagged through to the final destination or not.
That isn't true in general; YVR can handle intl->US bags directly through-checked when connecting from AC/AF/CA/CX/CZ/JL/LH/NH/PR/WS. See
Passenger Guides | YVR.
But I agree you should expect AF to refuse to through-check the bags and therefore to have to go landside to Canada.