The Gier is a French river that flows in a northeast direction through the Loire and Rhône departments. It is a tributary of the Rhône, which it enters from the right bank. The Gier valley was formerly heavily industrialized with coal and iron mines and factories.

The Rhône is a major river in France and Switzerland, rising in the Alps and flowing west and south through Lake Geneva and southeastern France before discharging into the Mediterranean Sea. At Arles, near its mouth, the river divides into the Great Rhône and the Little Rhône. The resulting delta forms the Camargue region.