Hi Marco,
I'm not in the mood for the city, as my haiku will show :)I just looked at you syllable count. I thought 5/7/5 was classic haiku. However, if that is not right, the second version will serve. This has the 3/5/3 count. Same sense, less words :)

Dissonance. Bustle.
Red. White. Black. Grey. The city.
Flowers blossom---where?

Dissonance
White. Grey. The City.
Flowers--Where?