The Austrian flag was created after the House of Babenberg. The House of Babenberg was a noble dynasty of Austrian margraves and dukes.
The colors of the Belgian flag were taken from the coat of arms of the Duchy of Brabant. The Dutchy Brabant was a state of the Holy Roman Empire.
The colors of the French flag represent liberty, equality, and fraternity. The colors also honor the french revolution.
All the colors of the Germanflag were made to represent the Weimar Republic. The Weimar Republic was made to assemble a new type of government in Germany.
The Luxembourger flag is based on a Grand duke's coat. the colors also represent a red lion in a white and blue striped field.
The Dutch flag is based on the three colors of Prince William of Orange, Its based on him because he led the fight for Dutch Independence.
The Swiss flag represents one of the coat arms of canton Schwyz. He was one of the found members of the Swiss confederation.