Called out by one of my favorite symphonic metal albums, featuring a Swedish band with an American singer covering French pop songs in metal covers. https://en.m.wikipedia.org/wiki/Les_Fleurs_du_Mal_(Therion_a...
By the way, while it’s not really metal, you might also like this live version of Sarah Brightman’s - Fleurs Du Mal: https://youtu.be/cOllWAhZhXY. It was filmed in Stephansdom Cathedral in Vienna and I went to visit it after seeing this video. It’s really impressive!