Outgoing French Finance Minister Nicolas Sarkozy has been confirmed as the new head of President Jacques Chirac's governing UMP party.
Nicolas Sarkozy has made no secret of his leadership ambitions
He replaces Mr Chirac's ally, Alain Juppe, who was found guilty in a party financing scandal.
Mr Sarkozy is widely expected to use the post to build up support for a presidential run in 2007 against Mr Chirac, his former mentor.
He won the party leadership ballot comfortably, with 85% of the vote.
The 49-year-old, seen as one of France's most popular politicians, will give up his ministerial post on Monday to take up the party chairman post.
Mr Sarkozy's election prompted cheering from thousands of supporters at the centre-right Union for a Popular Movement (UMP) congress outside Paris.
In a televised acceptance speech, Mr Sarkozy said he would use his new role to shake up France with reform.
"I am ready to carry your energy, I am ready to embody your hopes. I am ready as I probably have ever been," he told a crowd of 40,000 party loyalists.
"I am ready because I know deep inside that France no longer fears change but is waiting for it, and we are going to personify this change."
French Prime Minister Jean-Pierre Raffarin and Interior Minister Dominique de Villepin were among the ministers present.
President Chirac did not attend but was represented by his wife, Bernadette.
Just over half the UMP's 120,000 members took part in the vote, in which Mr Sarkozy stood against two rivals.
The BBC's Caroline Wyatt in Paris says French newspapers have been calling the UMP conference the anointing or coronation of Nicolas Sarkozy.
The "Sarko show", as one paper headlined it, is the most expensive party conference France has ever seen, with much of the money going on slick, US-style presentation.
The brashness of the event - and its meticulous planning - is seen in France as typical Mr Sarkozy, our correspondent says.
He is a charismatic man in a hurry to get to the very top, and he makes no secret of it, she adds.
The son of a Hungarian immigrant he has held two of the toughest jobs in the cabinet - first as interior minister, and - until Monday - as finance minister.
On the economy, he has shown a mixture of protectionism with a dose of unexpectedly liberal thinking, telling the French they must not be afraid of economic success and encouraging them to work harder.
At the interior ministry, he was tough on crime, yet liberal on many social issues. He believes France must do much more to promote ethnic minorities and integrate its large Muslim population.