French Justice Minister Christiane Taubira, a gutsy left-winger often considered at odds with her government on matters of law and order enforcement, resigned on Wednesday, President Francois Hollande's office said in a statement.
The announcement came as parliament prepared to examine a controversial constitutional reform that would allow for people convicted of terrorism to be stripped of their citizenship in certain circumstances.
Taubira, who expressed reservations about the plan, said on her Twitter account: "Sometimes you remain in place to resist. Sometimes resisting means you go."
The statement from Hollande's office said Taubira would be replaced by Jean-Jacques Urvoas, widely regarded as more supportive of Prime Minister Manuel Valls and Hollande.
Taubira, born in French Guiana on Feb. 2 1952, was perhaps best known for shepherding legislation through parliament to legalise same-sex weddings in France.
While her active role on that major social policy change was widely recognised, she was often accused of advocating a softer touch on law and order than others in her government.
That stance has looked even more problematic in the wake of the Nov. 13 Islamist militant attacks on Paris and the security clampdown they sparked, and as countries across Europe take a harder line on policing.
Her departure comes amid talk in French media of a possible broader shakeup of Hollande's team as it heads into its last full year before presidential and legislative elections in 2017.