White is the traditional color of the House of Bourbon, who ruled in France from the late 16th Century until the French Revolution. On the flag, the color white represents the King.
Red and Blue
The red and blue in the flag represents the city of Paris. Revolutionaries in Paris traditionally flew red and blue. Likewise, revolutionaries wore blue and red cockades (ribbons) on their hats when they stormed the Bastille in 1789.