A young couple,Simone and Jean, settles in the outer suburbs of Paris.They watch their neighbors live .Here,family life is compromised by the father's affair ;the mother,left to her own devices,cannot stop the elder son from running away.There, the family is in harmony:the children admire their dad .He entertains and educates them:we attend a lesson in astronomy.The teenagers on the block set up a pack.They steal Simone's moped .