I'm French and I can assure you that
Alizee is REALLY from the past ... and she has never been considered like a queen but more like a pop sensation of a moment! She was a big deal with her first singles/albums but from the moment she decided to stop working with Mylene Farmer she was over for the general public ! More she incarnated the phenomenon of singer for children in france and it's something not popular in my country since the early 2000 !
The only singers in France with the true "Queen" like statut are Mylene Farmer and Celine Dion (despite she is from quebec) !
Mylène Farmer is our equivalent of Madonna she was very creative and surpassed all boundaries for a french female singer in the 80's/90's ! Today even if she still sell it's more thanks to her great fanbase than anything ! She pop-up only when she releases an album gives an unique interview and that's it !
I think I don't need to explain who is
Céline Dion to anybody XD ? When she come in France all the medias unwraps her the red carpet !!
Patricia Kaas is a great contender too (personnal favorite)She was really big in the end of the 80's and the 90's and sold millions and millions of albums at that time ! She is a very strong vocalist and seems to have some great success in the countries of Eastern Europe for a french singer ! Today She did a lot of concerts around the world and is not really present in the french media but is still considered like one of the best french voice !