François Bayrou included Fesneau in his shadow cabinet; in this capacity, he served as opposition counterpart to Minister of Agriculture Bruno Le Maire.

He was subsequently unanimously elected to the presidency of the MoDem group in the National Assembly on 25 June; though Marielle de Sarnez had initially announced her intent to run, she ultimately decided not to.

Upon the inauguration of the government of Jean Castex in July 2020, the citizen participation portfolio was added to his title, which was changed to minister delegate.

In the 2021 regional election in Centre-Val de Loire (Centre until 2015), Fesneau led the MoDem list supported by La République En Marche!

[10] In October 2023, Fesneau participated in the first joint cabinet retreat of the German and French governments in Hamburg, chaired by Chancellor Olaf Scholz and President Emmanuel Macron.