This isn't all that bad of an idea, but I've had two other ideas for a useful Helsinki city state myself, which I think have modern historical precedent.

Helsinki as an Industrial city state:
+1 Diplomatic favor if your carbon emmissions penalty is 0.
An additional +1 from the Modern Era onwards
This is a reference to Finland's ongoing attempts at receiving recognition for their considerable forestation as a source of a carbon sink

Helsinki as a Cultural city state:
Receive a second free Rock Band unit upon purchasing a Rock Band.
This is reference to the overabundance of heavy metal bands originating from Finland

Your City State mods are great. My siblings play on the same game, and they didn't even know that they were mods

I have a suggestion for a city-state. Please do Phoenix, AZ it's my home state's capital. If it's possible can you make it a trade city-state and have the picture be a cactus?

As Finland will soon be in NATO, an actually useful suzerain bonus would be more appropriate. A sauna as a building or as an improvement would seem like a good choice for a suzerain bonus.

Fundamentally having Helsinki as this city state in the game is completely stupid and undermines a lot of potential in the game. Maybe if the suzerain bonus would give a defensive bonus or additional grievances against the aggressor if the suzerain were to be attacked, it would make a lot more sense.

Otherwise it's fun in general to have my country's capital as a city state, and the suzerain bonus I so eagerly criticize is actually quite clever. I give this a thumbs up, I love the moose even though the lion would fit better.

Haha love the moose

When Finnish neutrality is contagious.