And not really in the same crowd as the others. While the other acts listed are from various countries, they were all popular on American radio stations. Edith, not so much. I get that not all the answers should be easy, but Edith is a bit of an outlier. And I really doubt that she more popular than Elvis Costello or Ellie Goulding who were guessed less often.
Odd choice to include and it is unusual that she would score that high.
Whenever I hear "La Vie en Rose", all I can think of is Eileen Brennan in "The Cheap Detective". :-)