I found what seems to be a bug on Galactic Civilizations 3 (look in attachment). If you take a look at the screenshots, you can see that the consulate grants a bonus of 200 % on tourism per contiguity bonus, which is insane.
See screenshots of the game:
The first two planets, which have consulates in each, have an income of several thousands credits, while the others have, at best, around 60 income, with a taxation level of only 50 %.
This is due to a tourism of 400 and 200 % on each planet respectively.