1. Christophe Castaner held a vice presidency of the Regional Council of Provence-Alpes-Cote d'Azur from 2004 to 2012 under the presidency of Michel Vauzelle, before he represented the 2nd constituency of the Alpes-de-Haute-Provence department in the National Assembly from 2012 to 2017.
Christophe Castaner headed the Socialist Party list in the 2015 regional election in Provence-Alpes-Cote d'Azur, which saw the party lose all representation at the regional level.
In 2018, Christophe Castaner was appointed as Minister of the Interior following the resignation of Gerard Collomb.
The youngest of three children, Christophe Castaner's father was in the military and his mother was a housewife.
Christophe Castaner was technical adviser to Minister of Culture Catherine Trautmann in 1997 and became her principal private secretary in 1998.
Christophe Castaner was principal private secretary to Michel Sapin, then Minister of the Civil Service and State Reform, from 2000 to 2002.
Christophe Castaner won against incumbent Pierre Delmar, a member of the Rally for the Republic who had been mayor from 1983 to 1989 and again since 1995.
Christophe Castaner was reelected Mayor of Forcalquier on 23 March 2014 by 22 votes, standing against Sebastien Ginet of the Union for a Popular Movement.
In 2004, after having been elected to the Regional Council of Provence-Alpes-Cote d'Azur, Christophe Castaner was tasked by Regional Council President Michel Vauzelle with land use planning.
Christophe Castaner was reelected as a regional councillor in 2010 and given a new portfolio: employment, economy, higher education and innovation.
On 17 June 2012, Christophe Castaner was elected as a deputy to the National Assembly for the 2nd constituency of the Alpes-de-Haute-Provence department in the 2012 legislative election, ahead of the UMP candidate, Jean-Claude Castel, Mayor of Corbieres.
Christophe Castaner is considered to be one of Macron's earliest backers.
Christophe Castaner sponsored the Bill for Growth, Activity and Equality of Economic Opportunity, known as the loi Macron.
Christophe Castaner was spokesperson for and a supporter of Emmanuel Macron during the campaign for the presidential election of 2017.
Christophe Castaner justified his joining with Emmanuel Macron by explaining that in politics one must be "at the right place at the right time, without necessarily knowing where you will end up".
On 17 May 2017, Christophe Castaner was named Secretary of State for Relations with Parliament.
Christophe Castaner was appointed as Government Spokesperson for the Edouard Philippe government.
On 25 October 2017, a few days after Emmanuel Macron gave him his support, Christophe Castaner he declared his candidacy for the chairmanship of the La Republique En Marche party on RTL.
Christophe Castaner was elected at the first party convention on 18 November 2017.
In late 2018 and early 2019, Christophe Castaner was criticised for his handling of the yellow vests movement.
On 9 March 2019, after a day of yellow vests demonstrations, Christophe Castaner, a married man, was photographed in a nightclub in Paris with an unknown young woman.
On 1 May 2019, during Labour Day demonstrations, Christophe Castaner announced an "attack" of the Pitie-Salpetriere Hospital in Paris by demonstrators, as well as the aggression of the nursing staff and a policeman.
In July 2019, Christophe Castaner was again criticised for decorating five police officers who were the subject of a police brutality investigation.
Christophe Castaner had claimed that there were no warning signs prior to the attack in the suspect's behavior, while records dating back to 2015 documented several alerts and reports concerning a possible Islamic radicalisation.
In June 2020, Christophe Castaner announced a Black Lives Matter demonstration in Paris would be authorised to proceed despite a decree signed by the Prime Minister banning demonstrations as a result of the COVID-19 pandemic in France and although he had stated the week prior "gatherings were prohibited" in order to slow the spread of the virus.
Christophe Castaner was quoted saying about the fight against racism following the murder of George Floyd in the United States: "I believe that the global emotion, which is a healthy emotion on this subject, goes beyond the legal rules that apply".
In July 2020, Christophe Castaner was sacked and replaced as Interior Minister by Budget Minister colleague Gerald Darmanin in the new Castex government.
BFM TV published as a headline: "Christophe Castaner replaced by Gerald Darmanin after two years of controversies".
On 10 September 2020, Christophe Castaner succeeded Gilles Le Gendre as president of the La Republique En Marche group in the National Assembly.
Christophe Castaner was defeated in the second round of the 2022 French legislative election by Leo Walter of La France Insoumise and subsequently lost the seat he held since 2012.
In October 2020, Christophe Castaner was one of 48 LREM members who voted in support of a bill introduced by the Ecology Democracy Solidarity parliamentary group that would extend the legal deadline for abortion from 12 to 14 weeks.