The women's FKT was set in July 2012 by Emilie Lecomte at 41h22m10s. The previous record was by Stephanie Samper, 50h52m10s set in 2011. These records are discussed here (in French). Lecomte's sponsor, Quechua, produced a nice video (in French with English subtitles) about her run.
"She has set the bar high ... very high." - corsematin.com
Notably, 2-time UTMB champion Rory Bosio did the GR-20 in about 50 hours (fast, but not close to the record) in October 2017, as reported here (French).