So, I've been giving this a bit of thought, and this is what I've concluded:
Props: On the loosehead side, Domingo has no match at the moment imo. Ben Arous is a bit too green, so I'd put Forestier on the bench. On the tighthead side, Mas is a no brainer if fit, with Attoub on the bench. If Mas is not fit, then Attou starts and Debaty goes to the bench.
Hookers: Szarszewski and Kayser are a step above Guirado. I've no preference for the starter.
Locks: Mestri and Papé start, very clear here. Suta to the bench, a regular starter playing for the Top 14 leader and with several seasons of top 14 over a very promissing 20 year-old.
Back rowers: See at the end, this is the hard part.
Scrul-half: Parra is the best imo. Plus, his kicking is priceless. I don't really see why so many people want him dropped.
Fly-half: This is a hard one... Michalak is on better form than TD, but I'd still play TD because he knows Parra better.
Centres: Any pair of the four that includes Fritz. Mermoz-Fritz, Fickou-Fritz or Fritz-Fofana (in my view, Fofana is a much better 13 than 12)
Back three: Huget on form, Clerc on proven qualities, and Dullin on projection.
Now, the backrowers. My preferred one for the longer term would be Picamoles-Gunther-Chouly, but I can't see that happenning against Australia. It's a very muscly backrow, but with a lot of pace, technique and line-out ability. For this game, we may see Gunther-Nyanga or Ouedraogo-Picamoles, with Chouly on the bench.
I've actually made up my mind on two things: I don't want Lauret on the 23, and I don't want Nyanga and Ouedraogo playing simultaneously. That gives the following combinations, besides the three above:
Gunther-Nyanga or Ouedraogo-Chouly;
Nyanga or Ouedraogo-Picamoles-Chouly.