Janzé (Breton: Gentieg, Gallo: Janzae) is a commune in the Ille-et-Vilaine department in Brittany in northwestern France.

After the French Revolution, Janzé became an important center of agriculture and commerce and is currently well known for its poultry industry.

Janzé is located approximately 16 miles southeast of Rennes, the capital of Brittany, at the junction of highways D41 and D777.

[6] After the Revolution, Janzé was an important market for sailcloth produced from hemp grown in the surrounding countryside.

Other notable agricultural products included grain - rye, wheat, oats and buckwheat - and apples used to make cider.

Janzé was occupied by the Germans during World War II from 18 June 1940 until 3 August 1944, when the town was liberated by the American army.

The local poultry industry goes back at least to the 18th century, when the black chickens of the area were mentioned in a Breton dictionary.

[9] With the increasing interest in organic farming, it was discovered that the black chickens of Janzé are particularly good at eating insects that can decimate orchards, thus avoiding the need for chemical pesticides.

However, it can be argued that the local languages retained their "old" words and pronunciations simply because the way of life in the countryside stayed much the same over the centuries.

The deputy mayors are François Goiset, Anne Joulain, Pierric Morel, Elisabeth Barre-Villeneuve, Dominique Cornillaud, Isabelle Ceze, Jean-Paul Botrel, and Martine Pigeon.