Gilles-Louis Chrétien was a French cellist.
Chrétien was born at Versailles. In 1787 he invented a machine called a 'physionotrace,' with which he took portraits in profile from life. He worked initially with Edme Quénedey, but then went into partnership with the miniaturist Jean-Baptiste Fouquet, until the latter's death c. 1799. Fouquet produced the grand trait drawing, sometimes highlighted or coloured in pastel, which Chrétien then engraved in aquatint. Many of them are of great interest on account of the celebrity of the persons represented, 'L'Incorruptible Robespierre,' Mirabeau, and Marat being among the hundreds which he produced. Also Dutch patriots, like Johan Valckenaer, Samuel Iperusz Wiselius and Quint Ondaatje who fled to France or visited Paris ordered a set of physionoctrace. Chrétien died in Paris in 1811.