Yesterday, I picked up a book entitled The French Left 1762 - 2012: History, Politics and Imagination by Jacques Julliard. In the introduction, he mentions the colors used to signify the political right and left in France.
...[W]hite serves to designate the right, and the left is symbolized by various colors: sometimes blue, sometimes red.He notes that, while blue has always been political in its connotations, red, in the beginning, had a social connotation. Red has been more closely associated with the revolutionary left, which some see as constituting a third political strand, but Julliard argues is part of a broader left.
I know that our current usage of blue and red is due to an accident of how a couple of television stations chose to color the map during one election. However, I thought was interesting to learn what the colors symbolize elsewhere, especially since we get the terminology of "left" and "right" from the French.
I haven't gotten past the introduction yet, but so far it looks very promising. He traces, from the seventeenth century, the different strands of leftist thought in France. I've long been interested in how liberalism relates to other left of center movements, so this book promises to be especially interesting to me.