@Malick:
Coming from someone who has used that similar city setup before, some things I think you should consider:
-The two different street patterns make it look too busy/cluttered. Get rid of the diamond pattern, but edit it so that there are still little box/curb things around the garden area.
-Get rid of the two statues toward the front, the two stone flower things at either end, and those bright blue flowers in the upper left. It seems like you're trying to add a diversity of detail, but it's starting to look very cluttered.
-In nature, you'll find different trees together, but in a planned city garden, I think one kind of tree is fine. Also, I don't know for sure if this is the method of recoloring you used, but never, ever use Colorizing on trees because it ruins the contrast between colors. Use a program like the Gimp that can recolor separate areas of color at a time (most RTP-style trees have yellow, green, and cyan shades in them).
-Make the archway structure a tile taller. If there are steps and some kind of passage under it, it should be a little taller. Also, some of the bricks look warped and need adjusting. You should also add shadows underneath the arches to give them more depth (and make the steps lighter, too, so that they don't come out so dark in said shadows).
-You might want to get a better train. I know I made that one, but it was so long ago that I made it too small and it looks kinda strange. The way it came out, it's more suited for a scaled-down world map type thing (Stevo made an awesome example once, but I think it's lost). I'd use Zanyzora's bigger one instead.
-The flower autotile could do with some recoloring. The orange/white combo stands out a lot. Maybe go for something more red/pink to match the flower archway, or blue/purple to match the awnings.
-Lastly, the steely color of the lamppost stands out, too. Dull it down or give it a brownish tint to fit in better.