[3] Fourneyron became politically active in 1995 when Yvon Robert, the Socialist candidate for the Rouen City Council, asked her to join his team.

She faced the outgoing MP Patrick Herr, representing the right party UMP, in Seine-Maritime's first constituency.

After the campaign, she said that she was hurt by the harsh attacks against her: “I was accused of being a bad mother because I didn't stop my political career when I lost one of my sons in a scooter accident.

Fourneyron was chosen for a second time by the French Socialist Party for the 2007 legislative election.

On 9 March, she led a left-wing coalition and won against outgoing mayor Pierre Albertini in the first round, with 55.79% of the votes.

Other women who are mayors of cities this large include Hélène Mandroux, Maryse Joissains, Martine Aubry, Adeline Hazan, Dominique Voynet, and Huguette Bello.

In July 2011, Fourneyron joined Martine Aubry's campaign team, representing the French Socialist Party in the 2012 presidential election.

[9] On 16 May 2012, Fourneyron was appointed Minister of Sports, Youth, Popular Education and Community Life.

[10] One of François Hollande's 60 campaign promises was to prohibit MPs from holding multiple elected positions simultaneously, so this forced Fourneyron to resign from the Rouen city council.