A French-style rolling pin basically looks like a long piece of dowelling, or a chunk sawed out of the middle of a broomstick, with the ends sanded down.
They will be much longer than rolling pins common in the English-speaking world, anywhere from 45 to 50 cm long (18 to 20 inches), but narrower as well, only 4 to 5 cm in diameter (1 ½ to 2 inches).
They usually have no handles at the ends, though some will be a bit more tapered at the ends than others. Occasionally, one might have knobbed handles at the end, but it will still be all one piece of wood.
The tapering allows them to be easily spun or rotated while rolling, making it easier to make a better circle of dough — you can just swivel them on one end.
They are often made of beech or boxwood. Maple is a popular wood for ones made in North America.
To operate, you just press on it with the palms of your hands, moving it back and forth. They are easy to swivel and pivot.
Literature & Lore
Julia Child preferred French rolling pins to the standard North American ones.