It was a natural one, as he had directed Belmondo in three prior films, including 1983's The Outsider (Le Marginal), which had been a massive hit, whereas his next three, The Vultures, Happy Easter and Hold-Up, although quite successful, had not lived up to the star's lofty standards.

[7][8] Despite the contributions of former police officer Simon Michaël and Alphonse Boudard, an acclaimed novelist known for both intimate and hardboiled crime stories, the writing process was not a smooth one.

[5][9] As usual, several of Belmondo's close friends feature in the cast, such as Michel Beaune and Pierre Vernier, two of his classmates at the Conservatoire national supérieur d'art dramatique.

[10][9] Belmondo's then girlfriend, Brazilian model and singer Maria Carlos Sottomayor, also shows up in a musical number, in the final of her three on-screen appearances with the star.

[11] Shortly before this film, stage actor Jean-Pierre Malo had portrayed a ruthless hitman in Spécial Police, another hardboiled cop movie written by Simon Michaël.

[14] The Loner's shoot was memorialized in the short film Les Pros, directed by Florence Moncorgé, the daughter of Belmondo's erstwhile co-star Jean Gabin.

[9] At the time of the film's release, Belmondo was also starring in Kean, Jean-Paul Sartre's version of an Alexandre Dumas play, at the Théâtre Marigny, enjoying critical acclaim for his first stage work in thirty years.

[15] As a result, the majority of his promotional air time was dedicated to the play, rather than to the more conventional The Loner, which Deray partially blamed for the film's tepid commercial performance.

[22] However in the Soviet Union, where Belmondo's name still carried great mystique at this stage of his career, the film drew in a sizeable audience, with 27.8 million tickets sold.

Bernard Gérin of highbrow cultural magazine Télérama summed up the critical consensus, assessing: "If you have seen The Outsider, The Professional or The Night Caller, don't bother, you have already seen The Loner.

[5] The film was belatedly reviewed in the May 1987 issue of Studio magazine, where Christophe d'Yvoire wrote that "[Belmondo] seems to keep bringing up the miracle recipe that made him the number one star of French cinema.

Robert-Claude Bérubé of Canadian media watchdog fr:Mediafilm called the film "a succession of tropes, staged with a certain efficiency but not much enthusiasm by an experienced director."

"[27] Writing for state-sponsored Soviet film magazine Iskusstvo Kino, Sergey Lavrentiev opined that "[t]he plotline here is extremely simple, typical and familiar [...] Moreover, the general lethargy is not compensated for by the genre's seemingly obligatory brawls and shootings: in The Loner, they take up unforgivably little screen time.

It seems that Jacques Deray, as an experiment, decided to build a police thriller on dialogue alone, hoping that the commercial success of the film would be ensured by the mere fact that the main role was played by the irresistible Belmondo".

The rights to the film's over-the-air debut were acquired by TF1, by far the dominant force in French television, and delivered the expected audience, drawing an average of 12.1 million viewers for a massive 48 percent share on 9 October 1990.

[31] Some contemporary articles immediately saw the film as a death knell for France's traditional genre production, with Studio magazine writing: "The Loner signifies both the end of an era and the bankruptcy of a system.

He saw these films' loss of favor in a broader sociological context, writing that France's popular audience had stopped going out to the movies, and had only been partially replaced by a younger crowd that cared more about "images coming from elsewhere".

[16] In a retrospective assessment for his book on neo-noir cinema, Italian critic Pier Maria Bocchi was more positive, praising Belmondo's attempt to steer his career away from "the image that had always constrained him, that of an athletic man of action, in a difficult role devoid of cascades [in French in the original]", whereas Delon, "to the contrary, doubled down on the masculinity of a genre without future".

In addition to a score by British composer Danny Schogger, it includes two songs performed by Maria Carlos Sottomayor: "Life Time", which Polydor also released as a 7-inch single, and "Ecstasy", which served as its B-side.