Hi there. I have added a permalink to Gabrielle's birth record (no trace of the alleged middle name "Bonheur" there, and she was indeed recorded with the name Chasnel) and also a stub profile for her mother.
Not only is she going to be difficult to connect (as Wikitree has very few profiles of French ordinary people, as her parents were: same problem as Louis Braille) but her family will be extra difficult to trace, as they were itinerant as well as poor.
While I thank you all for pointing Coco Chanel's profile out, I can't help adding that (with my French bias) she would be less important than other French unconnected notables, for example Victor Hugo, Georges Clemenceau, Gustave Eiffel... Not to mention all those who don't even have profiles.
And Greg, thank you and you are correct, I for one did not know her profile was out there, yet I've been searching specifically for overlooked profiles of French notables...