Born in Morges, in Switzerland, the son of a painter and picture dealer, Jacob Sablet (1720–1798), Jean-François Sablet first trained with his father. In 1767, he entered the Paris Académie as a student of Joseph-Marie Vien, under whom his brother Jacques later studied as well. The brothers made their reputations in different genres: Jean-François (more commonly know as François) as a portraitist and Jacques as a history and genre painter. In his early career Francois excelled at landscape and occasionally painted genre scenes and even the odd mythological subjects. Jacques made a particular success of group portraiture and conversation pieces. This occasional cross-over between genres and the fact that Jacques was the more prolific and better known artist means that Francois’s work is often mis-attributed to his brother. In 1791 François left France to join Jacques in Rome where they stayed until February of 1793 when, just days after France declared war on Britain, Holland and Spain, the brothers were forced to leave Rome, along with the rest of the French community residing there. During this brief two year period François concentrated mainly on producing landscapes, and views of Roman ruins, several of which were later engraved by Francisco and Pietro Piranesi. He also made studies of the various local costumes of the Campagna.

Thanks to their delicacy, chromatism brightness, taste for small sizes and a kind of bourgeois intimism, the Sablet brothers belong to genre painters and portraitists current of the late XVIII century.