When sister shows Gilles to his room, he wants to hide something and the camera moves from him to the furniture. Then he approaches the furniture and removes the bottom drawer to hide something. The whole thing is done as to simulate one continuous shot, but discontinuity is apparent because of a sharp cut between shots.
When Ivette Faints and other sister arrives, the light in the house is on and the everything is brightly lit, but in the previous shots it was dark.
When woman is killed with a cleaver, she is clearly breathing after being killed.
When Jean is found dead in the cornfield, he is clearly moving his eyes despite being dead.
When one of the sisters is killed by a knife, it's clear that the knife is only leaving blood marks and making no wound.
When police arrive near Gilles's dead body, there is clearly a movement on his face despite him being dead.
Nurse stabs her attacker with a stick. It would take a lot of force to pierce trouser and flesh to stab someone with a stick like that.
When nurse returns to the house after she was attacked, she is calm and looks as nothing happened to her.
At the end when the Doctor is in the nursery, a cameraman can be seen reflected in the mirror.
Inspector Pierre decides to arrest Gilles as the author of the crimes only after discover that he was in jail a time before, but without proves of his guilty. After know that, Gilles tries to escape, although he has witnesses of his innocence, and with a gun for make the situation more complicated.