If they could get interline or codeshare deals with AF and/or KL, things could get very interesting; CDG alone has far more intl connections than LHR, let alone LGW and would probably steal quite a few pax.
I'd be very surprised if they started this route with anything but an ATR42. There were rumours a while back of a third ATR42, so maybe it's in connection with this?
Scheduling will be very important; as far as possible, they'll need to try and feed into/out of AF's or (preferably!) KL's hub timings at CDG/AMS. It would be great to get through fares from here (JER) to various international destinations - DXB, HKG, JNB etc.