Originally Posted by Courmisch

That's a known bug in the Finnair OLCI procedure. (Or maybe it's a feature https://thegeekwhisperer.com/2009/09/24/bug-vs-feature/)

The computer gives you priority security, boarding and presumably prints your status in the manifest. I guess that the marketing code is not included on the manifest, so the crew just treats you as any Oneworld frequent flier. This works in both directions, so you also get Accès No.1 at CDG 2D. Presumably, this works for other non-OW marketing codes on AY metal too, such as CA, FI or TP. But I have never had the opportunity to try (and am not looking forward to it either).

The mileage credit will go to Flying Blue, assuming you did bind the AirFrance PNR with your Flying Blue account. You can also reassociate your FB number manual at the check-in desk - but that is only useful if you have status with Flying Blue.

For the sake of comparison, AirFrance online check-in pages list Finnair Plus as a possible FFP. But it (and nothing else) works if and only if the flight is marketed by Finnair.