Belgian Frites - French Fries
To my understanding, frites are double fried. You wash, peel, and cut the potatoes (thicker, as you noted)*, then fry the potatoes at a lower temperature (325F is what I usually do). Then you let them drip the excess oil off on a wire rack or stack of paper towels, toss to coat them in cornstarch and fry again in hotter oil (400F). They're also usually fried in smaller batches in shallower oil than tradition shoestring fires. 
The really cool thing with them is that you can freeze them between the two fry times, so you can basically have your own frozen fries ready to go at any time. 

*Drop the cut potatoes in water to prevent discoloration and then dry them a bit before frying if you're cutting a lot.