Member of the National Assembly
Orphelin was elected to the French National Assembly on 18 June 2017, representing the 1st constituency of Maine-et-Loire.[5]
In the National Assembly, Orphelin served on the Committee on Sustainable Development, Spatial and Regional Planning. He was also a member of Joint information mission on plant protection products.[6] In addition to his committee assignments, he chaired the France-Vanuatu Friendship Group[7] and served as secretary of the France-India Friendship Group.[8]
In September 2018, Orphelin supported Barbara Pompili's candidacy for the presidency of the National Assembly. The following month, he launched a collective called "Accelerating the Ecological and Solidarity Transition!", which brought together more than 120 MPs from six of the seven parliamentary groups of the Assembly. Led by Orphelin, Aurélien Taché and Hugues Renson, a group of around 20 members of the LREM parliamentary group was established in late 2018 with a "wish to express a humanist, social and ecological sensibility and to better raise citizens' concerns"; the initiative was widely interpreted as the launch of a left-wing faction within the group.[9]
Orphelin left the La République en marche group on 6 February 2019, explaining having "done everything possible [...] to carry high the ecology", without success, invoking in particular insufficient progress on the "climatic, ecological and criticizing "certain choices" of the government. He is close to the former Minister of Ecological and Solidary Transition Nicolas Hulot, who resigned in 2018 for the same reasons.[10]
In May 2020 he became one of the two initial presidents of the Ecology Democracy Solidarity National Assembly group, which was mainly made up of defectors from LREM.[11]