To make a vast but nonetheless (I believe) true generalization, in France there is a distrust or wariness of capitalism that seems extreme to most Americans. One of the many manifestations of this attitude is the strict control of competition.
For example, stores are allowed to put wares on sale (soldes) only twice a year during regulated periods: the winter and summer sales. One of them is right now, until the 29th of July this year. July is a great time to shop in Paris.
Look for signs that say "2e démarque" or "3e démarque"-- this means the second or third reduction in price.