History of the colours of the flag of France

Fleur-de-lis

For centuries under the House of Valois and House of Bourbon, France did not have a single official "national flag," relying instead on royal standards. The best-known design was a blue field featuring golden fleurs-de-lis (the royal arms), simplified by King Charles V around 1376 to three golden fleurs-de-lis on blue (France moderne).

The white flag

Under the Bourbon dynasty (such as Henry IV), plain white fields—sometimes with a white cross or royal coat of arms—became common military and royal ensigns. 

Birth of the Tricolour (1789–1794)

The Paris cockade (July 1789)

Right before the storming of the Bastille, the Paris militia adopted a cockade of blue and red, which were the traditional colors of Paris. 

Adding white

General Gilbert du Motier, Marquis de Lafayette, added the traditional royal color white to the militia's cockade, creating a blue, white, and red tricolour cockade to symbolize unity between the king, the city of Paris, and the people. 

Official adoption (1794)

The National Convention passed a decree on February 15, 1794, making the blue, white, and red vertical tricolour the official national flag of the French Republic (with the blue stripe placed on the hoist side). [1]

The colours of the flag of France

The official shade of the blue stripe on the French flag has experienced two significant adjustments in the modern era, oscillating between a historic dark navy and a lighter, brighter cobalt. Because the French Constitution does not explicitly specify exact color hex code - stating only that the emblem is the "blue, white, and red" tricolour—these adjustments have been implemented through presidential and administrative decisions rather than legislative reform.