In France , the thick - cut fries are called " Pommes Pont - Neuf " or simply " pommes frites " , about 10 mm ; thinner variants are " pommes allumettes " ( matchstick potatoes ) , ±7 mm , and " pommes paille " ( potato straws ) , 3–4 mm ( roughly ⅜ , ¼ and ⅛ inch respectively ) .