Audoin-Rouzeau worked at the French National Centre for Scientific Research (CNRS), which she joined in 1988. She later joined the Institut Pasteur, as a eukaryotic archaeologist. She has undertaken a project on the epidemiology of the Black Death and bubonic plague, the result of which was a work considered definitive in the research area: Les chemins de la peste (Pest Roads) (2003).

Fred is the diminutive of her given name, Frédérique, while Vargas derives from the Ava Gardner character in the film The Barefoot Contessa. Her twin sister Joëlle, a painter, adopted the pseudonym of Jo Vargas.

Vargas writes mostly police thrillers (policiers). She found writing was a way to combine her interests and relax from her job as a scientist. Her novels are set in Paris and feature the adventures of Chief Inspector Adamsberg and his team. Her interest in the Middle Ages is manifest in many of her novels, especially through the person of Marc Vandoosler, a young specialist in the period. Seeking Whom He May Devour was shortlisted by the British Crime Writers' Association for the last Gold Dagger award for best crime novel of the year in 2005.

In 2006 her next novel, The Three Evangelists, won the inaugural Duncan Lawrie International Dagger. She also won the award in 2008 with Wash This Blood Clean From My Hand. She was the first author to be shortlisted for three successive novels. In 2009 Vargas was again awarded the International Dagger, becoming the first author to receive it for three successive novels. The International Dagger also recognizes the translator, in each case Siân Reynolds.

Fred Vargas took an important part in the defence of Cesare Battisti, a left-wing activist sought by Italian and French justice since 2004 for alleged assassinations committed in the 1970s, during the "Years of Lead".

Three Evangelists series

• Marc Vandoosler, known as Saint-Mark: Historian specialising in medieval life
• Lucien Devernois, known as Saint-Luke: Historian specialising in the Great War (inspired by Vargas's brother Stéphane Audoin-Rouzeau)
• Matthias Delamarre, known as Saint Matthew: Historian specialising in prehistory

*These three characters, christened the Evangelists, live in the same house, The Disgrace with Old Man Vandoosler

• Armand Vandoosler: former police Commissaire, Marc's godfather, epicurean and oddball
• Ludwig Kehlweiler: former policeman with a national network of informants and a toad Buffo

Adamsberg series

• Commissaire Jean-Baptiste Adamsberg: peripatetic police chief, with Zen research methods
• Adrien Danglard: methodical police inspector, Adamsberg's deputy. Divorced, father of five children and conspicuous white wine consumer
• Camille Forestier: a musician/plumber who has a turbulent relationship with Adamsberg.

The Three Evangelists

• 1995 - Debout les morts; English translation: The Three Evangelists, 2006, (Prix Mystère de la critique)
• 1996 - Un peu plus loin sur la droite
• 1997 - Sans feu ni lieu

Commissaire Adamsberg

• 1996 - L'Homme aux cercles bleus; English title: The Chalk Circle Man, 2009
• 1999 - L'Homme à l'envers; English title: Seeking Whom He May Devour, 2004, (Prix Mystère de la critique)
• 2000 - Les quatre fleuves; English title: The Four Rivers. Graphic novel (with Edmond Baudoin).
• 2001 - Pars vite et reviens tard; English title: Have Mercy on Us All, 2003, (Prix des libraires)
• 2004 - Sous les vents de Neptune; English title: Wash This Blood Clean from My Hand, 2007
• 2006 - Dans les bois éternels; English title: This Night's Foul Work, 2008

Other novels

• 1986 - Les Jeux de l'amour et de la mort (Prix du festival de Cognac)
• 1994 - Ceux qui vont mourir te saluent

Essays and other works

• 2001 - Petit Traité de toutes vérités sur l'existence
• 2003 - Critique de l'anxiété pure
• 2004 - La Vérité sur Cesare Battisti