From left to right, what national flags are shown in the picture?

From left to right, the national flags are of Russia, of France, of Luxembourg, and of the Netherlands.

All of these four flags are tricolour featuring three bands colored white, blue and red, either vertically or horizontally. Russian flag is a horizontal tricolour of white, blue and red from top to bottom. French flag is a vertical tricolour of blue, white and red from left to right. Both of the flag of Luxembourg and the flag of the Netherlands are horizontal tricolor from top to bottom, with the most noticeable difference which is that Luxembourg’s flag has lighter shades of red and blue than Dutch flag, and a less obvious difference which is that Luxembourg’s flag is slighter longer.

These three colors carry different symbolic meanings in each country. In Russia, red represents courage, generosity, and love, white represents nobility and frankness, and blue represents faithfulness, honesty, impeccability, and chastity. French "tricolore" flag is an emblem of the Fifth Republic. It had its origins in the union, at the time of the French Revolution, of the colors of the King (white) and the City of Paris (blue and red). Red, white and blue, the three colors in the Luxembourg flag, stand for vibrancy, revolution, and power, harmony, peace, and innocence and perseverance and determination, respectively. In the Netherlands, red represents the people, white represents the church, and blue represents the nobility.