The French Socialist candidate for the presidency, Ségolène Royal, has said she wants to embody change if she becomes France's first woman head of state next year.
Ms Royal was the clear winner (60.62%) in a ballot of party members last night.
Speaking after her victory, she said she wanted to write a new page in French history.
Ms Royal is likely to face Interior Minister Nicolas Sarkozy, the expected nomination from the right, in next April's election.
The result represented a clear setback for the left of the party championed by former Prime Minister Laurent Fabius, which accused Ms Royal of looking to push the Socialists more to the centre.
Former Finance Minister Dominique Strauss-Kahn came second in the primary with 20.835% of the vote, while Mr Fabius came last with 18.55%.
Officials said 82% of the Socialists' 219,000 members voted yesterday, underscoring the strength of Ms Royal's mandate.
