Early beginnings

Hazan joined the Socialist Party in 1992 and Lionel Jospin's campaign team ahead of the 1995 presidential election.^[3]

Member of the European Parliament, 1999–2008

As part of the Party of European Socialists, Hazan served on the European Parliament's Committee on Civil Liberties, Justice and Home Affairs. In this capacity, she was the parliament's rapporteur on the introduction of the European Arrest Warrant.^[4]

Hazan was also a substitute for the Committee on Legal Affairs, a member of the delegation for relations with the Mashreq countries, a member of the delegation to the Euro-Mediterranean Parliamentary Assembly, and a substitute for the delegation for relations with the Maghreb countries and the Arab Maghreb Union.

Mayor of Reims, 2008–2014

Hazan was elected mayor of Reims in the 2008 local elections thanks to the lack of unity of right parties. She competed against former minister Catherine Vautrin.

Ahead of the Socialist Party's 2008 convention in Reims, Hazan publicly endorsed Martine Aubry as candidate to succeed François Hollande at the party's leadership.^[5] Since the convention, she has had the nickname of "La Bonne" (the Maid) after Aubry's phrase at the 2008 Reims Congress of the Socialist Party: "T'aurais pu faire le ménage Adeline" ( "Adeline, you should have cleaned the house", after seeing a spider on her desk during her candidacy speech.)

Hazan was not re-elected in the 2014 elections, when she obtained only 42.75% of votes of citizens; consequently, her Republican competitor, Arnaud Robinet became mayor of Reims in April 2014.