I have witnessed this many times as well, while I (a white woman) have never been stopped there.
They do seem to be stamping passports pretty regularly now.
Ok, white guy here, carrying European passport -- and stopped an avg. of 1/year at CDG over the past decade and a half. Not that much of a hassle, compared to waiting for baggage delivery (when having checked-in bags, that is).....
Never gotten a stamp in my passport, though....