French Salon (Observatory):
The Salon is an observatory which gives a free artist. It might not seem like much, but for cultural victories it can be quite nice.
Possible Synergies:
Okay, first of all, with the patch, Louis can now build cheap theatres and libraries! He is creative and the +2 culture is only a small amount, but the cheap buildings is great. In fact, Louis gets libraries, theatres, coliseums and forges at half production cost. Not too shabby.
Given the anarchy caused by switching to Mercantilism perhaps going from liberalism to astronomy makes sense. Of course you have to build these Salons, but they are cheaper than universities and with Notre Dame the free artist gives more culture for the same amount of science boost (+25%. Not only that, but you get GGP. Maybe you do want to switch to Mercantilism and then you have got two free artists with the library, salon, (and university) the Statue of Liberty is not that far away with his cheap forge and quicker building of the Statue of Liberty. Either way you could have 2-3 free artists. And speaking of science boost, why not run Representation with those free artists? Use the library, salon and uni to beeline for the ECWs and you are laughing. C'est formidable! C'est magnifique! D'accord?
Possible Drawbacks?
Not sure what Napoleon would do with the free artist other than maintain culture borders on resources on a crowded map, but then again you could build a cheap theatre in the likely small city first. You could however have your larger cities with these GAs and go and culture bomb you new acquisitions.
Summary:
There are likely some other possibilities to be discussed as there seems to be lacking a certain "je ne sais quoi?", but this UB should not be taken lightly.
I didn't read all your entries, but having just finished a SG game playing Louis, I thought I'd give you some more insight.
First, I don't understand what you say about mercantilism, anarchy and such.
It's pointless IMHO. You can still go mercantilism if you feel the need.
And democracy isn't just next door. It's still a good deal away from astronomy.
I would simply mention that with mercantilism + SoL, a salon and a theatre, you could have 3 free artists.
I don't know why you mention Notre Dame. It's a nice wonder, but it has nothing to do with the salon.
Maybe you meant Sistin Chapel , giving +2CPT for every specialist?
One more thing to notice is that artists give 4 cpt and 1 beaker, even without representation. Under representation, it's 4 cpt and 4 beakers. +25% science boost, it's 5 free beakers in every city (+ library, it's 6 free beakers)... La vie est belle!
Beware : The salon is very helpful in a cultural game, but it can be damageable if you want other specialists (it pollutes the GP pool). In fact, in the GP farm, if you build a salon, you have 2 sources of artists.
So even if you run 4 scientists, you still have 33% odds of getting an artist.