"After four days of treatment and rest, Bernadette Chirac left the Pitie-Salpetriere hospital Friday evening," their son-in-law Frederic Salat-Baroux told AFP.
Jacques Chirac, 83, who was admitted to the hospital on September 18, "remains hospitalised and continues to receive treatment and care for his lung infection," said Salat-Baroux, husband of Chirac's daughter Claude.
Chirac, who led France from 1995-2007, had just returned from a visit to Morocco with his wife when he was admitted to hospital.
On Wednesday, Salat-Baroux said Bernadette Chirac, also 83, had been admitted to the same facility.
He said she was "profoundly affected by the death of her eldest daughter Laurence (in April) and exhausted for several days following the lung infection of her husband."
The centre-right Chirac, who served two terms as head of state, is probably best remembered internationally for his opposition to the US military intervention in Iraq in 2003.
A small stroke while in office in 2005 weakened him, and he is now rarely seen in public.
In December 2015, he spent two weeks in hospital, suffering from what his family described as fatigue.