Determining desired length, shape, and materials will help you choose the best French rolling pin. Depending on how much effort you want to spend cleaning the rolling pin, a wood, silicone, or stone one may be your best option. If you roll out a lot of dough circles, a tapered pin may work better than a straight one. Choose a rolling pin that is the standard length unless you have a lot of experience baking.
A French rolling pin may be a straight rod, or it may taper slightly from the center of the rod to the ends. You may prefer a tapered rod, especially if you have trouble rolling out a thin, even round of dough. The tapered ends prevent the dough from rolling out too thin on the ends and too thick in the center. If you are rolling out a straight rectangle more often than a circle of dough, a straight pin may more useful, though.
You'll most likely find a French rolling pin made out of wood. The best wood for a French rolling pin is a hardwood that won't crack or warp. Birch and maple are common options. If you don't think you'll be able to care for and oil an uncoated pin, you may want to choose one that is polished with a thin coating of wax. The wax coating keeps flour and water from damaging the wood over time.
French rolling pins are also made out of materials such as granite, stainless steel,and silicone. A silicone rolling pin is easy to clean and won't cling to the dough. It doesn't have the heft of wood, though. Granite rolling pins are very heavy, which can detract from the pin's overall usefulness. As they are made of stone, they stay cold and prevent the butter and fat in pastry dough from heating up and melting as you roll it out.
Stainless steel French rolling pins are easy to keep clean. They are usually cut straight across and aren't available in tapered versions. You can place a steel French rolling pin the refrigerator to chill it before rolling out dough.
Most French rolling pins are between 19 and 21 inches (48 and 53 cm) in length. A shorter rolling pin will be difficult to use to roll out a full-sized pie dough but may work well for small doughs. Unless you are a professional baker or very experienced in using rolling pins, you'll want to avoid very long pins, as they can bow in the center.