TinaBee

Hi - no not kidding. The French system can seem bizarre and you may find that journalist as a profession is a protected group. I am sure I read somewhere that a freelance journalist (journaliste pigiste) had to have an employment contract with clients and could not be registered as AE. It is quite likely that there is another profession, e.g. newsletter writer (I'm guessing), that CAN register as AE, but you need to be very careful not to fall foul of French "closed shop" professions.

EuroTrash

That's absolutely correct. The French journalist unions fought hard for this, to ensure that journos get full social security rights, because so many publishers were abusing the system and the profession badly needed protection.
However there is a little wrinkle that allows regional correspondents of national publications to have freelance status, I suppose because they are more loosely attached to their employer and only ever work remotely.
Anyway to get round it I registered as an 'écrivain public', which sounded close enough to me, but to cover my back I did include being a regional correspondent in the bit where you list more specific details about what you actually do (I think the form you fill in is different now though). And guess what they've put down as my activity on INSEE certificate that you get to confirm your status... yep, 'Journaliste'.