No. of cities maintenance:
Cost = B(p) * n / 2
where
n = number of cities you own
B(p) = is a value according to your pop (in the city you want to know the maintenance for) and this table
For a map sized Standard and Monarch difficulty you have to multiply the value by 0.85. I assume it will be +-0.05 per difficulty level above or below Monarch.
Distance maintenance:
dist.maintenance = (7 + p) * (d * 0.29) / 8
where
p = population in the city you look at
d = distance to a city with a palace(-like building)
Distance is measured 1 per tile for horizontal or vertical movement and 1.5 for diagonal movement. The tile of the palace-city does not count, the tile of the city you want to know the maintenance of does.
For a map sized Standard and Monarch difficulty you have to multiply the value by 0.8.
And as always all numbers are rounded down, in the case of distance maintenance it seems to the second decimal. No. of cities maintenance is rounded to the second decimal but then rounded to the nearest 0.05 multiple (sorry I have no clue how to describe that in English). Basically you calculate the value, divide it by 5 and round it to the second decimal than multiply it by 5.
Example:
Rosseau is a city with 3 pop that is 4 distance from the capital. In total I have 8 cities
No. of cities maintenance (NM) = FLOOR(B(p) * n / 2 * 0.85 / 5;2) * 5
NM = FLOOR(0.66 * 8 / 2 * 0.85 / 5;2) * 5
NM = FLOOR(5.28 / 2 * 0.85 / 5;2) * 5
NM = FLOOR(2.64 * 0.85 / 5;2) * 5
NM = FLOOR(2.244 / 5;2) * 5
NM = FLOOR(0.4488;2) * 5
NM = 0.44 * 5
NM = 2.20
Distance Maintenance (DM) = (7 + p) * (d * 0.29) / 8 * 0.8
DM = (7+3) * (4 * 0.29) / 8 * 0.8
DM = 10 * (4 * 0.29) / 8 * 0.8
DM = 10 * 1.16 / 8 * 0.8
DM = 11.6 / 8 * 0.8
DM = 1.45 * 0.8
DM = 1.16
Cost = B(p) * n / 2
where
n = number of cities you own
B(p) = is a value according to your pop (in the city you want to know the maintenance for) and this table
For a map sized Standard and Monarch difficulty you have to multiply the value by 0.85. I assume it will be +-0.05 per difficulty level above or below Monarch.
Distance maintenance:
dist.maintenance = (7 + p) * (d * 0.29) / 8
where
p = population in the city you look at
d = distance to a city with a palace(-like building)
Distance is measured 1 per tile for horizontal or vertical movement and 1.5 for diagonal movement. The tile of the palace-city does not count, the tile of the city you want to know the maintenance of does.
For a map sized Standard and Monarch difficulty you have to multiply the value by 0.8.
And as always all numbers are rounded down, in the case of distance maintenance it seems to the second decimal. No. of cities maintenance is rounded to the second decimal but then rounded to the nearest 0.05 multiple (sorry I have no clue how to describe that in English). Basically you calculate the value, divide it by 5 and round it to the second decimal than multiply it by 5.
Example:
Rosseau is a city with 3 pop that is 4 distance from the capital. In total I have 8 cities
No. of cities maintenance (NM) = FLOOR(B(p) * n / 2 * 0.85 / 5;2) * 5
NM = FLOOR(0.66 * 8 / 2 * 0.85 / 5;2) * 5
NM = FLOOR(5.28 / 2 * 0.85 / 5;2) * 5
NM = FLOOR(2.64 * 0.85 / 5;2) * 5
NM = FLOOR(2.244 / 5;2) * 5
NM = FLOOR(0.4488;2) * 5
NM = 0.44 * 5
NM = 2.20
Distance Maintenance (DM) = (7 + p) * (d * 0.29) / 8 * 0.8
DM = (7+3) * (4 * 0.29) / 8 * 0.8
DM = 10 * (4 * 0.29) / 8 * 0.8
DM = 10 * 1.16 / 8 * 0.8
DM = 11.6 / 8 * 0.8
DM = 1.45 * 0.8
DM = 1.16
). I've taken some screenies just a day or two ago but they are already several turns old so it is really hard to give an overview that is not immediately outdated. But a few turns from now there will be a quieter period after the settling frenzy and the empire should be stable enough that an overview can be done with some hopefully valuable insights on what and why I did it. 
But I got me one of your German women 