The French flag (le drapeau francais) adopted in 1794 is blue, white and red, similar to our American flag of “red, white and blue.” The Marquis de LaFayette is thought to have been responsible for creating the colors. They were used in Paris on the day of the storming of the Bastille.
The flag is divided into three equal vertical stripes signifying, according to Flags of the World:
Blue is the color of Saint Martin, a wealthy Gallo-Roman officer who ripped his blue cloak with his sword to give one half of it to a poor person who was begging him in the snow. This is the symbol of care and the duty that the wealthy had to help the less fortunate.
White is the color of the Virgin Mary, to whom the Kingdom of France was consecrated by Louis XIII in the 17th century; it is also the color of Joan of Arc, under whose banner the English were finally driven out of the Kingdom (15th century). White became logically the color of Royalty. The King's vessels carried plain white flags at sea.
Red is the color of Saint Denis, the patron saint of Paris. The original oriflamme (war banner) of the Kings was the red oriflamme of Saint Denis.