I was just curious. Did they all choice it because it looks nice, or is it have some meaning behind it?
Well in France, the flag came about when King Louis XVI entered into France in 1789, after being forced out of Versailles by the mob. The Red and Blue represent the colours of the city of Paris, and the white represents the Bourbon white colour; but more generally as well the colour of "ancient France".
Source: History of Modern Europe, John Merriman.
And after that it came to represent "revolutionary" France, a break from the old symbols and standards of monarchial Europe.
hi! you'll find more on this in the FAQ (link on sidebar):
If you look at countries using red-white-blue combination in their flags, you can separate different groups.
Panslavic colors, red white and blue are used by Slavic countries. These colors can be dated back to the middle ages, even though the pattern became really popular during the rise of Nationalism. The use of these colors symbolizes the unity of Slavic people. Russian flag is often the basis for these flags. Examples : Russia, Czech Republic, Slovakia, Slovenia, ... Most of these flags have a horizontal setting.
Revolutionary Republics: Blue, white and blue are associated with the ideals of freedom, equality and brotherhood. Countries using these colors often had an important Revolution. Colors can also be associated with communism, as in the North Korean flag. Examples: USA, France, Haiti, Liberia...
UK and former British colonies: Red originates from the English Flag, featuring a St Georges Cross, most likely since the Crusades. Blue and white are from the Scottish flag, using the Saint Andrew cross. The combination made the UK flag, used in the canton of many former British colonies. Examples: UK, Australia, New Zealand, Hawaii...
Other national histories / symbolism. Example: Nepal (blue for peace, red for victory...)
