Martine Aubry is known as the architect of France's 35-hour work week
Martine Aubry is the new leader of France's Socialist Party (PS), after she narrowly beat former presidential candidate Segolene Royal.
She campaigned on a platform that called for anchoring the party firmly to the left.
The Mayor of Lille since 2001, Ms Aubry has carved out a reputation as one of Ms Royal's fiercest rivals, opposing her both in style and substance during the battle for the party leadership.
She now faces an uphill battle to rebuild party unity after months of bitter campaigning exposed deep internal divisions.
Ms Aubry was widely regarded as one of the stars of Prime Minister Lionel Jospin's Socialist government before she left in 2000 to campaign for the post of the Mayor of Lille.
As employment minister, she was behind some of the government's most distinctive policies.
They included the 35-hour working week - known in France as the "Aubry Law" - as well as an important youth employment scheme.
By the time she left, Mrs Aubry had taken credit for unemployment in France falling below 10% for the first time in many years.
When she won the mayorship of Lille in 2001, it was seen as a possible springboard for a higher position - prime minister or even president.
Born in Paris in 1950, Martine Aubry is the daughter of former European Commission President, Jacques Delors.
She joined the PS in 1974, rising through the ranks until she was appointed minister of labour in 1991 by then Prime Minister Edith Cresson.
In 1997 Lionel Jospin made her minister of social affairs and employment and she became one of his most effective and popular ministers.
In a surprise result in the 2002 general election, she lost her seat in the National Assembly to centre-right UMP candidate Sebastian Huyghe, who then challenged Mrs Aubry as Lille mayor.
However, she was comfortably re-elected as mayor in March 2008.
Mrs Aubry has published several books on local government, human resources and current affairs.