Monkwarrior
My mother language is russian, but I'm dreaming learn spanish someday
I tried made script in your way with advice threads, but again without success. Cheked all several times started new campaign but it seemes that script doesnt' run.
There is one condition that not very suitable for me "SettlementIsLocal". In this way script affects only on human player but I suppose that AI suffers from overflowing cities much more than player. I want include all settlements on the map in the script and I believe that decrease of population can improve AI behaviour.

alpaca
I tried your syntax and it doesn't work
If I put your original script nothing happened.

I tried add "and Carthago SettlementPopulationMaxedOut" beacuse in docudemon written that SettlementPopulationMaxedOut need settlement. In this way population level decrease till 400 men on next turn.

I tried run script without conditions
Code:
declare_counter break_counter
monitor_event SettlementTurnStart Carthago
console_command add_population Carthago -7000
set_counter break_counter 1
end_monitor

while TrueCondition
if I_CompareCounter break_counter = 1
set_counter break_counter 0
end_if
end_while
In this way nothing happened.
If I leave only and I_CompareCounter break_counter = 0 as condition the population level fall till 400 men level on next turn.
I tried different syntax with your code but I cannot discover any solution to make "SettlementTurnStart" work. It seemes that "ButtonPressed ButtonPressed end_turn" works better but in this way end turn button triggered console_command and script run without checking "SettlementPopulationMaxedOut".

Any new ideas gladly appreciated!