Looked it up, here's a clickable Steam link:
https://store.steampowered.com/app/2287430/Metropolis_1998/The graphics remind me a little bit of the ones in OpenTTD (an open source transportation tycoon game), the top down view also looks interesting, since most games just stick to one perspective. Oh, maybe the style is a little bit like the Simutans game (another transportation tycoon), but that depends on the graphics package.
I don't think that anyone has quite done city builders where you can look inside of buildings, so that sounds pretty unique - good luck with your project. I'm pretty sure that the genre is big enough for Cities: Skylines II, niche games like Urbek City Builder (voxel based city builder where building placement matters, almost like a puzzle) and plenty of other games out there, so don't feel too discouraged.