"We showed him a black and white puppy."
Translation:Nous lui avons montré un chiot noir et blanc.
No, because they are a bit more specific in French and tend to leave out less. The lui means 'to him' so we, to him, showed the puppy, or we showed the puppy to him. You wouldn't say 'We showed the puppy him' (unless you were showing the person to the puppy) so lui is used instead of l' here.