[citation needed] On 3 June 2003 Lassalle stood up in the National Assembly during questions to Minister of the Interior Nicolas Sarkozy and sang the Occitan anthem Se Canta in protest at an announcement by Sarkozy concerning the housing of 23 gendarmes tasked with guarding the Somport tunnel, which links France with Spain through the Pyrenees.

As he explained in an interview with France 3 later that day, Lassalle took exception to what he saw as a slur on the Pyrenean village and decided to interrupt the minister with his song.

The firm claimed that this relocation of its investment would not result in the closure of the Accous site, but Lassalle's concerns were not assuaged and he embarked on a hunger strike on 7 March.

The strike ended on 14 April, when Toyal offered an assurance to Minister of the Interior Nicolas Sarkozy that the factory would not close and that it would continue investment in the area before expanding elsewhere.

Earlier the same day, Lassalle had been admitted to hospital in Garches, in the western suburbs of Paris, prompting intervention by President Jacques Chirac, Prime Minister Dominique de Villepin and Sarkozy.

The bank from which he borrowed the money took his credit card as a guarantee, forcing his mother-in-law to provide groceries for the family during Lassalle's campaign.

[11] A few days later, he publicly stated he was thinking about withdrawing his candidacy for the presidency, citing a lack of sufficient media coverage.

[12] Lassalle ultimately received just over 3 percent of the vote, a significant improvement over his 2017 showing, with his strongest support coming from Corsica, Nouvelle-Aquitaine and Occitanie.

[14] He did not run in the 2022 French legislative election, instead endorsing his brother for the seat, which was ultimately won by Socialist Party candidate Iñaki Echaniz.

[15][16] Lassalle ran in the 2024 European Parliament election, where his list received 2.35% of the vote, falling short of the 5% threshold required to gain seats.

Son of an Occitan shepherd, he is trained as an agricultural technician but got involved in politics very early, becoming at the age of 21 mayor of his native village.

On 20 September 2020, Lassalle accidentally parked his car on a level crossing that later obstructed a passenger train, which was reported on by multiple news outlets.