I used to think France. But then I discovered Songhai.
They've got a very powerful UA, and their UB basically gives them France's UA.
The mosque is nice but I think France is better due to opportunity costs and the fact that at the start of the game you can expand without your policy costs taking a hit in terms of turns per cost.
In fact, it's something like the 4th or 5th city where france begins to see the effects of increased policy costs. If you're building monuments as if your a regular civ, your policy costs essentially remain unaffected by expanding.
Songhai may be better for overall cultural gains, but it requires investment. France is about opportunity cost. It's simply a pleasure to watch your turn count toward your next policy go
down upon placing a new city. Or at the very least, stay the same.
Having said all that, I can't decide between india, france, or babylon. Persia, Greece, Siam, and China are all great too. In fact those 7 civs are probably the top tier in my book. Close runner up being Rome since there are so many universal buildings in civ5... everyone benefits from culture, everyone benefits from happiness, everyone could use a science or wealth building or two, etc. It's like having a workshop from the start of your games.
In fact the only bad UA's in my book are ottoman's and America... I don't think the "whole package" deal explains away Ottomans... look at China: all three of their Unique bonuses are fantastic. As is the case with Greece.