It may pass for trivial , but you must remember that the subject was not that much frequent in the movies in 1977 : it was made two years before "Kramer vs Kramer" and depicted the life of a father left alone to take care of his only child .
Like its American counterpart ,there's no financial problem ,for papa is an engineer,and he makes sure that his son's schooling does not suffer for it : the first scene ,before the cast and credits ,is a dictation :although spelling does not seem to be thee offspring's forte, he shows himself a clever kid " these sentences are devoid of interest" ;for that matter he is right ,and his dad finally agrees.
By and large ,it passes over the real problems in silence ,but the lines are often funny and the rapport Claude Brasseur has with his son wins the audience over.
Many clichés of course : the new woman in papa's life (played by the excellent Nathalie Baye)the son depicts as " a bum selling potatoes from door to door" ;the schoolteacher in a sexy dress trying to seduce the new bachelor (certainly the worst scene).
Sonny has dangerous acquaintances : Dédé ,a young hoodlum (Daniel Auteuil) urges him and his best friend to help him steal the betting office money ;it's the most hilarious moment in the whole film ; but the moral conclusion ,as well as the ending ,are disappointing : as this movie is not to be taken seriously ,some madness would have been welcome.
