To raise taxes you must build a tax office (I think), but there is no way to raise or lower taxes,the tax office produces a certain amount of gold per turn like the market.

Yea ... I feel that you should be able to raise taxes in an individual city (but -1 prestige per tax level increased)

also, it should require a tax office to be built. (tax revenue should increase based upon # of economic buildings, gold output, and population)

Otherwise ... tax offices should give more moneh

I get the impression that Taxes aren't in yet.
If you check the Kingdom Report income from "Buildings" is separated from income from Taxes, and a there are a bunch of other sources that don't seem to do anything.