From @mastödantirâfami commentthese sources, that would be a baie de gaylussaquier.
Baie (like berry) is the generic term for these small fruits but gaylussaquier (gaylussacia) is new to me although I recognize Gay Lussac in it. Gaylussaquier was coined after the Latin name Gaylussacia that was given to this plant in the early 19th century.
As already answered, airelle is another generic name that come to mind in French to name such fruits:
Source: Dictionary of the French and English languages, F. E. A. Gasc, London, 1877
This particular one is also named airelle corymbifère:
Source: Second rapport du Comité sénatorial chargé de recueillir des renseignements sur les produits alimentaires naturels des Territoires du Nord-Ouest et sur les meilleurs moyens de conserver et d'augmenter ces ressources, Ottawa, 1887.