Just for a reference, I'm Qantas Gold (Oneworld Sapphire) and was flying BA in business class early Dec from CDG to LHR and was not allowed to use the AF lounge. Even though they allowed paid access, they wouldn't let me in, even as a paid customer. I'm not sure if this is correct or not - but Oneworld pax appear not to be allowed.
This is correct - it's clear on the oneworld website that the AF lounge is only for JL pax (when it comes to oneworld airlines).