Film gris ( [film ɡʁi] , French for "grey film"), a term coined by experimental filmmaker Thom Andersen, is a type of film noir which categorizes a unique series of films that were released between 1947 and 1951. They came in the context of the first wave of the communist investigations of the House Un-American Activities Committee.  
Films gris offer a leftist criticism of society in general, and of capitalism in particular. They typically examine such themes as the psychological damages of class, the false promises of middle class happiness, and the pitfalls of materialism. 
Film gris differs from film noir in some of the following ways:
Andersen identifies the following  as films gris:
Film noir is a cinematic term used primarily to describe stylish Hollywood crime dramas, particularly those that emphasize cynical attitudes and motivations. The 1940s and 1950s are generally regarded as the "classic period" of American film noir. Film noir of this era is associated with a low-key, black-and-white visual style that has roots in German Expressionist cinematography. Many of the prototypical stories and much of the attitude of classic noir derive from the hardboiled school of crime fiction that emerged in the United States during the Great Depression.
A film genre is a stylistic or thematic category for motion pictures based on similarities either in the narrative elements, aesthetic approach, or the emotional response to the film.
Robert Siodmak was a German film director who also worked in the United States. He is best remembered as a thriller specialist and for a series of films noirs he made in the 1940s, such as The Killers (1946).
Crime films, in the broadest sense, is a film genre inspired by and analogous to the crime fiction literary genre. Films of this genre generally involve various aspects of crime and its detection. Stylistically, the genre may overlap and combine with many other genres, such as drama or gangster film, but also include comedy, and, in turn, is divided into many sub-genres, such as mystery, suspense or noir.
Neo-noir is a revival of film noir, a genre that had originally flourished during the post-World War II era in the United States—roughly from 1940 to 1960. The French term, film noir, translates literally to English as "black film", indicating sinister stories often presented in a shadowy cinematographic style. Neo-noir has a similar style but with updated themes, content, style, and visual elements.
The heist film or caper film is a subgenre of crime film focused on the planning, execution, and aftermath of a significant robbery.
Charles McGraw was an American stage, film and television actor whose career spanned more than three decades.
Pulp noir is a subgenre influenced by various "noir" genres, as well as pulp fiction genres; particularly the hard-boiled genres which help give rise to film noir. Pulp noir is marked by its use of classic noir techniques, but with urban influences. Various media include film, illustrations, photographs and videogames.
Adele Jergens was an American actress.
A semidocumentary is a form of book, film, or television program presenting a fictional story that incorporates many factual details or actual events, or which is presented in a manner similar to a documentary.
Critical criminology is a theoretical perspective in criminology which focuses on challenging traditional understandings and uncovering false beliefs about crime and criminal justice, often but not exclusively by taking a conflict perspective, such as Marxism, feminism, political economy theory or critical theory. Critical criminology frequently takes a perspective of examining the genesis of crime and nature of 'justice' within the social structure of a class and status inequalities. Law and punishment of crime are viewed as connected to a system of social inequality and as the means of producing and perpetuating this inequality. Critical criminology also seeks to delve into the foundations of criminological research to unearth any biases.
Steven Geray was a Hungarian-born American film actor who appeared in over 100 films and dozens of television programs. Geray appeared in numerous famed A-pictures, including Alfred Hitchcock's Spellbound (1945) and To Catch a Thief (1955), Joseph L. Mankiewicz's All About Eve (1950), and Howard Hawks' Gentlemen Prefer Blondes (1953). However, it was in film noir that be became a fixture, being cast in over a dozen pictures in the genre. Among them were The Mask of Dimitrios (1944), Gilda (1946), The Unfaithful (1947), In a Lonely Place (1950), and The House on Telegraph Hill (1951).
Marxist criminology is one of the schools of criminology. It parallels the work of the structural functionalism school which focuses on what produces stability and continuity in society but, unlike the functionalists, it adopts a predefined political philosophy. As in conflict criminology, it focuses on why things change, identifying the disruptive forces in industrialized societies, and describing how society is divided by power, wealth, prestige, and the perceptions of the world. "The shape and character of the legal system in complex societies can be understood as deriving from the conflicts inherent in the structure of these societies which are stratified economically and politically". It is concerned with the causal relationships between society and crime, i.e. to establish a critical understanding of how the immediate and structural social environment gives rise to crime and criminogenic conditions.
Tito Alonso (1926–1979) was an Argentine film actor.
Tech-noir is a hybrid genre of fiction, particularly film, combining film noir and science fiction, epitomized by Ridley Scott's Blade Runner (1982) and James Cameron's The Terminator (1984). The tech-noir presents "technology as a destructive and dystopian force that threatens every aspect of our reality."
Thom Andersen is an American filmmaker, film critic, and teacher best known for his works of experimental film, including his 1975 film Eadweard Muybridge, Zoopraxographer and the 2003 essay film Los Angeles Plays Itself.
The Lawless is a 1950 American film noir directed by Joseph Losey and features Macdonald Carey, Gail Russell and Johnny Sands.
Thriller film, also known as suspense film or suspense thriller, is a broad film genre that evokes excitement and suspense in the audience. The suspense element found in most films' plots is particularly exploited by the filmmaker in this genre. Tension is created by delaying what the audience sees as inevitable, and is built through situations that are menacing or where escape seems impossible.
A gangster film or gangster movie is a film belonging to a genre that focuses on gangs and organized crime. It is a subgenre of crime film, that may involve large criminal organizations, or small gangs formed to perform a certain illegal act. The genre is differentiated from Westerns and the gangs of that genre.