The first film directed by Costa-Gavras, The Sleeping Car Murders was based on a novel by Sebastien Japrisot. During a Marseilles-to-Paris overnight train trip, a girl is found dead in a sleeping car. As Paris detective Yves Montand steps up his investigation, more and more passengers turn up murdered. The unlikely climax is the only sore point of this otherwise well-wrought mystery. Bereft of the politicizing of Costa-Gavras' later works, The Sleeping Car Murders exhibits the director's fondness for American "film noir" thrillers. The film first hit Parisian movie screens under the title Compartiment Tueurs.
~ Hal Erickson, All Movie Guide