Une si jolie petite plage aka Such a Pretty Little Beach (1949) Classic French Noir

Directed by Yves Allégret.

Written by Jacques Sigurd, Cinematography by Henri Alekan. Music by Maurice Thiriet.

The film stars Madeleine Robinson as Marthe, Gérard Philipe as Pierre Monet, Jean Servais (Rififi) as Fred, André Valmy as Georges, Jane Marken as Mme. Mahieu, Paul Villé as M. Curlier, Christian Ferry as  "Le pupille" The Orphan, Yves Martel as The Old Man, Gabrielle Fontan as The Old Woman, Gabriel Gobin as Arthur, Mona Dol as Mme. Curlier, Julien Carette as The Traveling Salesman.

Jean Servais as Fred

Madeleine Robinson as Marthe

Gérard Philipe as Pierre Monet

Story

Off Season. Night, Rainstorm. On the road to Barneville-Carteret. Resort town. Normandy. France. 

A night bus, it's headlights pinpoints in the dark, traveling along the coast. The bus is almost to it's terminus. Besides the driver there are three passengers an old woman, a railroad employee, and A young man. 

The last stop, is Barneville-Carteret, and the woman and railroad man get off immediately followed by the younger man Pierre who hesitates at first them heads towards the only hotel open in the off season.

His entry surprises the occupants of the lobby, Madame Mahieu who owns the hotel, a traveling salesman, and Madame Mahieu's father the "Old Man." They are of course curious about this off-season stranger. The "Old Man" is a mute invalid, victim of a stroke, he sits in a wheelchair, and seems a bit more agitated about Pierre's arrival than the others.  

Pierre mentions that he is a student and in conversational interactions with the hotel personnel and the locals who gather there socially (its the only open establishment in the off season) he appears to be familiar with the area, and yet, his unexplained presence now gathers suspicion. 

Pierre eventually develops a friendly relationship with Marthe the hotel maid / waitress. Pierre also takes an interest in the 15 year old orphan boy "Le pupille" who works as the hotel go-fer. 

Jane Marken as Mme. Mahieu and Christian Ferry as "Le pupille"

Things start going Noirsville when Fred, another stranger, arrives who takes an interest in Pierre combined with Pierre discovering that "Le pupille" is being groomed by a much older predatory woman which triggers him into action.  

Noirsville 

Jacques Sigurd's storyline is quite similar to the one Billy Wilder, Charles Brackett, and D.M. Marshman Jr. wrote for Sunset Blvd., there though, the tale concerns the "voluntarily", predatory relationship between the has been movie star. and the wanna be screenwriter. This tale concerns the tragic aftermath, of the relationship between a predatory older woman and a teenager.

Yves Allégret creates a Visually and thematically bleak Noir, for me it in the same neighborhood as Il Grido and Damnation. You could also compare it to The Kill-Off (1989) a not quite as doomed Jersey Noir based on Jim Thompson's novel. The Kill-Off is also set in an off season, sea side, beach town, but it has an amusement park, it's one open bar, and it's various denizens that fills in for the hotel in Une si jolie petite plage. The Kill-Off  is set on Raritan Bay, which is a more lower rent vacation destination compared to the gems farther South along the Atlantic Coast. It also has some amusing sequences. 

No amusing sequences here , watch it when you are in the mood for it. 7/10