The Dutch flag and the French flag are similar because they share a common history. The colors of both flags, red, white, and blue, were popular during the French Revolution, and were adopted by many countries as symbols of freedom and democracy. The Dutch flag, in particular, has its roots in the 17th century, when the Dutch Republic was fighting for independence from Spain. The colors were chosen to symbolize the House of Orange (the Dutch royal family), who were leading the fight for independence.
The flag used to be in the colors orange, white and blue. But later they changed orange to red. Also the French were inspired by our Dutch flag hence the similarities now. Actually they are the "same" colors, but I do notice that indeed both the blue and the red colors are slightly different from each other.
dowath