Monaco, who were bought last season by Russian oligarch Dmitry Rybolovlev, have 73 points, five ahead of FC Nantes in second with one game to play.
Eight times French champions Nantes will also return to the top flight after four seasons spent in Ligue 2 as a 1-0 win against already-relegated Sedan earned them promotion.
Third-placed Guingamp, the 2009 French Cup winners, also secured promotion with a 1-0 victory at GFC Ajaccio.
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