Mori_Yuki: Just placing buildings in a sandbox style game without any challenge, filling 20 arrondisements with pre-made buildings, changing some sliders to alter rotation and size, slapping on pre-made textures on blocks, taking a snapshot, rinse and repeat is not what I am looking for. I would like to be able to recreate Léo Malet's Paris or the city as it was in the 18th and 19th century!

So my question is will it be possible to design custom buildings for the game and place them? Certainly in a game carrying the word 'Architect' in its name this must be possible! I would even go further, a game like this can't do without an asset editor allowing me to create custom buildings.

Without this isn't going the game I can see myself playing when there is Sim City (2000, 3000, ...) and Cities Skylines.

HydreeNoire: Hello!

To give you an answer to your questions, it's possible to create custom buildings via external software and add them on Mod.io to use them in game.
There may even be buildings you need for your project on this resource.
I put the link here: https://tap.mod.io/

If you have any other questions or requests don't hesitate.
Have a nice day!