Catherine is a servant girl working for the local mayor and victim of the sharp tongues of the mayor's wife and her friends. This is made clear in a first scene where she is asked to get the key of the mayor's desk at a cultural party the wife is attending. She is harassed by the whole elite who dislike the intrusion of the maid. In this scene it's made clear also that the wife has a secret lover who will later challenge the mayor's political career and will use Catherine as a scapegoat for his own ambitions. This role of "bad guy" is played by Renoir himself. The mayor who is fond of Catherine and is afraid that she'll be more victimized by his wife asks his sister to give Catherine a position in her own household. The sister has a son with tuberculosis (role played by Dieudonné). He's so weak he has no success with women of his class but of course Catherine will like instantly this fragile man. He dies after kissing Catherine while the rest of the town is celebrating carnival. The kissing scene at the window mixed with the fireworks is a brilliant moment of silent melodrama. Catherine is in mourning and because of that driven away by the mayor's wife and her friends. It is indecent that a servant girl is in mourning and shows public affection for someone who is not from her own social status. The emotions of Catherine are the element of disorder in the social ordered world of the rich. Catherine goes away and hides in a cheap hotel in the city where she is also bullied by a local pimp who sees in her an easy target to exploit. By accident Catherine is seen in the hotel window with the pimp, so more reason for gossip by the elite. When she returns to the village looking for a job she is rejected everywhere, even by the local Christian relief organization of which the mayor's wife became president. She meets the mayor again who is shocked by the attitude of the town, takes her in his home again and promotes her to his secretary. The wife is furious of course and leaves her husband to live with her mother. It is start of a slander campaign against the political credibility of the mayor. The lover of the mayor's wife sees what is happening as a golden opportunity and makes a public attack on the moral character of the mayor (what's new under the sun?) Catherine wants to avoid the downfall of her protector and leaves the mayor, explaining herself in a note. She hides in an old tram for the rain while the mayor is driving around in his car frantically looking for the girl. Two vagabonds are thrown out of a pub and out of frustration push the tram car, so it starts a crazy race up and down the hills towards the bridge and the valley abyss. Catherine is already accepting her death but is saved in time by the mayor who has made his choice for the girl. The social implications of his choice are not shown but are clear for all.
Source : IMDb