Batho began her militant activity in the high-school students' union FIDL (Fédération indépendante et démocratique lycéenne) while attending the Lycée Henri-IV in Paris.

Following nearly two months of strikes the movement obtained from Lionel Jospin, the Minister for Education, a pledge to spend 4.5 million francs[2] on renovating high schools and to protect certain student rights.

In 2003, during the breakup of the socialist left, she remained loyal to Dray, who employed her at the Île-de-France Regional Council, where she was responsible for security matters.

Her thoughts on security matters were taken into account by Ségolène Royal, the PS's candidate in the French Presidential Election of 2007, who incorporated them into her "just order".

[5] Batho declared her intention to be a candidate for the leadership of the Socialist Party at the Aubervilliers Congress in 2018,[6] but her application was ultimately rejected due to a lack of support.

[10] On 2 July 2013 the President of the Republic announced that he was terminating Batho's duties as Minister of Ecology, Sustainable Development and Energy following an interview in which she described as "bad "The 2014 budget of his ministry and admitted" [his] disappointment with the government ".

[12] During the 2017 French legislative election, Batho was re-elected with 56.94% of the vote against the LREM's candidate, Christine Heintz (43.06%), who had preceded her during the first round and had received the support of Ségolène Royal.

[15] In November 2019, Batho's amendment to the anti-waste bill, aimed at banning Black Friday promotions by including them as "aggressive commercial practices", was adopted in committee.

[16][17] On 2 May 2018, Batho announced that she would be leaving the Socialist Party and that she will take over the helm of Ecology Generation in September, succeeding Yves Piétrasanta.