The prize is one of the most prestigious awards in French cinema and often acts as a harbinger of further trophies to come.
Actor-turned-director Jean-Pierre Darroussin was awarded the Louis Delluc prize for best first feature for his Le Pressentiment in which he also had a starring role. The film was produced by Agat Films, Bac Films and France 2 Cinema and released by Bac in France in October.
The win for Lady Chatterley, meanwhile, marks the second year in a row that French sales company Films Distribution has handled a winner.
Last year's top prize went to Philippe Garrel's Les Amants Reguliers.
Lady Chatterley has been sold in Japan and Germany with many American buyers circling.
The Louis Delluc prize is voted on by a 15-person jury of industry professionals and is presided over by Cannes Film Festival president Gilles Jacob.