There are at least four different artists under this name:
1) Gris is a black metal band from Quebec, Canada, formerly known as Niflheim. "Gris" means "grey" in French. They have released two full-length albums to date: "Il était une forêt..." in 2007 and "À l'Âme Enflammée, l'Äme Constellée..." in 2013.
Official blog: http://musique-grise.blogspot.com
Official site @ archive.org: