Sorry if this has been asked before but I am a bit confused about this issue. I have a JL-ticketed J flight on AF metal for an intra-European flight (>750 miles). Do I earn SCs, given that this is technically a OW flight? I was told otherwise and that's why I'm now confused about it.
It depends on the programs involved.
For QFF, you either need to be flying on a QF codeshare (eg QF coded EK or AS flight) or have both marketing and operating carriers be oneworld members to earn SC.
QF8414 will earn SC and points, while EK414 (the same flight as QF8414) will only earn points.
QF4025 will earn SC and points, while JL36 (the same flight as QF4025) will earn SC and points at a lower partner rate.
As AF is not part of oneworld, flying a JL coded, AF operated will earn nothing.
The returning QF codeshares on AF will earn SC and points when booked as QF, and will earn nothing when booked as AF.
On the other hand, other oneworld programs allow limited earning on oneworld codeshares operated by non oneworld carriers. (eg, you can earn BA points on QF8414)