Have you seen the book 'Paris in Colour' by Nichole Robertson?
Her blog is lovely too. What makes her photos so distinctive is the focus on a single colour. I really want to try this idea-I have taken photos where I look for certain colours, but other colours distract. I might go for a Greenwich colour walk. I loved how, in Paris, there seems to be a moped of every possible colour, and pretty often a 2CV too!