Potage - Velouté - Soup all that different names for a ….Soup.
Not only, you know French people are very picky when we talk about food. :-)
Soup is most of the time broth and vegetables. Could be warm or cold.
Potage is probably more elaborated, using vegetables and some flavored ingredients.
Velouté is a potage using a egg yolk as a binder and heavy cream. A little more technique because the yolk cooks fast. This is more smooth than the others “soups”.