This page explains in detail the interactions between the Mario series and the Sim series.
SimCity on the SNES[]
december 31, 1990
Mario
Sim
In this version of SimCity, the monster attack is replaced with Bowser's attack. A description screen tells that he ended up in SimCity while searching for Mario and Luigi, and he's symbolically shown having wheels. In-game, though, he looks just like in the Mario series, but he's giant, being of Godzilla-like dimensions.
The change is also obviously applied to the monster attack scenario "Tokyo, 1961", describing Bowser's attack in the introduction.
Also, if the player's city has a population of 500,000 residents, the player will earn a Mario statue.
Comprehensive view of the city area.
Finally, one of the two unlockable scenarios, called "Free City U.S.A.", has as the only geographical feature a forest in the center of the map in the shape of Mario's face. This scenario is set in the year this game was released (1991) and the only task is to build "Marioland".
SimCity 64[]
february 28, 2000
Mario
Sim
Just like in the SNES game, a statue of Mario is unlockable, but this time it's in 3D, being based on Super Mario 64's graphics.
SimCity DS[]
February 22, 2007
Bowser's Castle in SimCity DS.
Mario
Sim
Bowser's Castle makes an appearence as a landmark for the player's city, unlockable after beating the "Sudamer" scenario.
License[]
While created by Maxis, all this games were licensed by Nintendo, being on Nintendo consoles, so they had the rights to include references to the Mario series.