While they don’t go as well together as other colours, this is a superb example of how to pull it off:
It works well here because the brown suit ia s mid tone brown, while the blues are either very dark (shirt stripe, necktie) or very light (handkerchief). To make it even better, he matches it all with a caramel colour briefcase. Lighter browns with reddish tones can work well with dark blues, and very light blues can work really well with dark browns.
Not surprisinging, this man is Florentine and featured on The Sartorialist blog. See here: The Sartorialist: On the Street….Via Della Vigna Nuova Florence
P.S. The quality of the photograph, with the muted lighting, and the soft yellow/green walls and the terra cotta planter in the background, make it look even better. Then again, all the shots on this blog are great.