I found something, maybe for Blake, don't know:
I played a Monarch game and found out, Louis is going for a cultural win. I was able to capture one of his 3 culture cities and hoped to prevent it this way, but i was wrong. He had a replacement city with 26k culture and started to push this one further. I tried to wage some more war against him and bribed other AIs into it, but since he had mighty friends, i wasn't able to stop him, but at least slowed him down by a large margin since i forced him to tech again and so release the culture slider. He still won, but that's because i played crappy.
So much for the story, the point is that his 3rd culture city gained only 96 culture per turn once the slider was set to 0 and he did not push the slider to earn his win and so needed 12 turns to get from 48900 to 50k, 10 of them simply wasted (none of his culture cities was in danger). Also his capital had 120k culture when the game ended, that's maybe a bit overdone.
I have seen 5 culture wins by AIs so far and altogether they were played quite decent (fastest one was 1904 AD, not too shabby), but the AI does a quite bad job in evening out culture between the 3 cities and also in the endgame to claim the victory. I also observed that they always use the culture slider (until threatened) and don't concentrate too much on artists.