One does not have much to expect from Maurice Cammage :a master ,so to speak , of the coarse comedy ,often dealing with the joys(?) of the military service and its grumpy warrant officers and its hopeless grunts.When he would live the barracks , make way for the husbands ,wives, lovers, cuckolds in civilian life , what the French call "théâtre de boulevard" ;one really plumbs the depths of stupidity."La Belle De Montparnasse " belongs to the second category .Plot : a husband who has not cheated on his wife after twenty years of marriage, decides to take the plunge, encouraged by an obese friend ;his plan is luminous :he chooses a fiancé for his beloved daughter ;this future son-in-law must have a mistress he will break up with and dad-in-law will replace him in the arms of the deserted woman .Taken aback ,a young man who wants to marry the daughter -but who sleeps with the obese friend's wife and who wants to keep it secret - chooses the first to come to play the role of his would be lover : but this neighbor, La Belle De Montparnasse ,is a tart de luxe ,has many lovers and finds it hard to accept a part in which she's abandoned , even though it's just a trick . The rest of the plot (based on a play) follows suit :everybody cheats on everybody ,except for the faithful husband -so far - and his authoritarian missus."I'm NOT a wife one can deceive!"Third-rate acting , but an extra-star for Pauline Carton, who plays her game well in this maelstrom of silliness.La Belle De Montparnasse, who keeps her accounts as though she were in a firm , is played by Jeanne Aubert ,who was primarily a singer :she performs a song and the movie is almost a musical,beginning with a farandole of revellers who enjoy eavesdropping ( a bit-brace is useful when many people wants to get an eyeful).It has to be seen to be believed!