Ne le criez pas sur les toits (1943)

Professor Moucherotte is about to discover a revolutionary fuel ,the formula of which is coveted by industrialists who would be ruined by this new product ,as well as an impostor,Bontagues,who would like to claim all the merit of the invention for himself ;the scientist dies,and everybody believes that his assistant holds the key to the secret whereas this dreamer,Fleuret ,actually tries to make flowers immortal.And now the poor guy is chased by the police and the villains.