Dominique de Villepin has been named as France's new prime minister, following the country's rejection of the EU constitution in Sunday's referendum.
Mr de Villepin was best known as foreign minister during the Iraq war
The former interior minister replaces Jean-Pierre Raffarin, who tendered his resignation following the vote.
President Jacques Chirac promised cabinet changes after the referendum, in which almost 55% voted "No".
Correspondents say the result reflects domestic discontent as well as wider anxiety about the European project.
Mr Chirac had campaigned for the "Yes" vote, along with government and main opposition parties.
He is due to address the nation on Tuesday evening to present a policy for the new team, which is expected to govern until elections in 2007.
Mr Chirac has not yet named other members of the new government.
But reports say Nicolas Sarkozy, the leader of the ruling UMP party, will return to the interior ministry, a post which he held before Mr de Villepin.
Mr Sarkozy is one of France's most popular politicians, and seen as a possible future president.
Mr de Villepin formally took over from Mr Raffarin in a brief handover ceremony at the prime minister's official Matignon residence on Tuesday afternoon.
As he left, Mr Raffarin received the customary round of applause from Matignon personnel gathered on the courtyard steps.
"For three years he has shown exemplary courage in the service of our country," Mr de Villepin said of his predecessor.
Mr de Villepin, 51, is best known abroad for expressing France's implacable opposition to the war in Iraq at the United Nations.
He is also regarded as a consensual politician and is personally loyal to Mr Chirac.
But the BBC's Caroline Wyatt in Paris says that as a career diplomat never elected to public office, he of all candidates most typifies the French elite so roundly rejected by the French people on Sunday.
After Mr Raffarin resigned, he said in a TV broadcast that he had made his decision independently of the EU vote.
He attempted to justify his attempts to reform France, but acknowledged these had not been accepted by the French people.
"I have always been aware that what is healthy for the nation does not go unblamed by public opinion," he said.
Opinion polls suggest that Mr Raffarin was one of France's most unpopular prime ministers since the Fifth Republic was set up in 1958.
He offered his support to his successor, who needed, he said, to continue the vital European project.