Implementing a 2D city map with (mostly) free movement

Hello,

how would one implement a 2D city map like this www.youtube.com/watch?v=tFEUuDBNAJw#t=543 (link blank)?

The map itself seems to be consisting of tiles, yet the movement is (mostly) free and has pathfinding working.

2.5D ?

The map does contain tiles and its difficult to see but the players are following the tiles , they just flow across them. Should be fairly simple to implement , it seems to zoom in.