French Justice Minister Christiane Taubira quit Wednesday, apparently in protest at government efforts to strip convicted French-born terrorists of their citizenship if they have a second nationality.
Taubira, popular among the ruling Socialists of President Francois Hollande but a target of criticism from right-wing politicians, tweeted: "Sometimes to resist means staying, sometimes resisting means leaving."
The outspoken 63-year-old, who is from French Guiana, became France's most senior black politician when she was named to the justice ministry post in 2012.
She has often been at the center of controversy, whether as the victim of racial slurs or as she forged the country's same-sex marriage bill despite fierce opposition from conservatives in the country.
Her latest battle saw her unable to see eye-to-eye with members of her own party over the controversial "loss of nationality" measure.
Hollande called for the measure to be written into the constitution in the aftermath of the November attacks in Paris which left 130 people dead.
It is part of a string of reforms meant to boost security as hundreds of French citizens — many holding dual nationality — leave to fight alongside Islamic State in Iraq and the Levant (ISIL), and in the case of the attackers, return to wreak devastation in France.
"Removing French nationality from those who blindly kill other French in the name of an ideology of terror is a strong symbolic act against those who have excluded themselves from the national community," Prime Minister Manuel Valls said after the measure was announced.
But many in the Socialist party see the proposal as an act of ideological treason that discriminates against one part of the population.
Just a day before the reforms were presented, Taubira announced the measure would be dropped, only to be overruled at the last minute by Hollande.
The reforms also aim to inscribe the right to declare a state of emergency into the constitution, including powers to raid homes and place people under house arrest without judicial oversight.
Valls will present the revised constitution to parliament Wednesday, and the debate starts in early February.
Hollande named Jean-Jacques Urvoas, the current president of the parliamentary laws commission, as Taubira's successor to "carry out ... the constitutional reform," according to a statement from the presidency.
One of the main criticisms of the nationality clause is that it will drive a wedge between those who are only French, and those who hold a second nationality.
A law already exists that allows for naturalized citizens to be stripped of their nationality.
But political scientist Patrick Weil told Agence-France Presse in December that France would become "the first democracy in the world" to enshrine in its constitution the principle of unequal treatment of dual nationals.
Parliamentary sources said Wednesday that the phrase "dual citizen" would not feature in the reforms to avoid this discrimination.
But it was not clear if this would allow purely French citizens to be stripped of their nationality, creating stateless citizens, which has been another debate in the country.
The measures have been praised by right-wing politicians.
Far-right National Front leader Marine Le Pen said Taubira's resignation was "good news for France".
Taubira, who tweeted that she was "proud" of her time in office, has previously admitted it was "very hard" at times as she was repeatedly called or depicted as a monkey by far-right politicians and magazines.