Written by Steve Pemberton and Reece Shearsmith and directed by Guillem Morales, the episode is set in a sleeper carriage on a French train.

The episode stars Pemberton, Shearsmith, Julie Hesmondhalgh, Mark Benton, Jessica Gunning, Jack Whitehall and George Glaves.

"La Couchette" draws upon the literary tropes associated with stories, such as Murder on the Orient Express and Strangers on a Train, following characters unknown to one another while travelling.

[4] In addition to Pemberton, Shearsmith and Whitehall, "La Couchette" stars Julie Hesmondhalgh, Mark Benton, Jessica Gunning and George Glaves.

[4][8] Shearsmith said that the writers aimed to exploit the intimacy of the setting; the unusual situation which is created by trying to sleep in what is potentially a room full of strangers.

Nonetheless, she had "such a fun week" filming the episode, noting that, despite the limited space on-set, it is "amazing how quickly you become institutionalised".

For Shearsmith, the small space added to the need to meticulously plan the production process; he explained that every shot was worked out in advance.

[9] The set, which was situated in Twickenham Studios for the filming,[8] was shaken manually by an assistant director to create the effect of motion;[8][10] something which surprised Hesmondhalgh.

Maxwell is disturbed first by Jorg (Pemberton), a drunk, flatulent German who climbs into bunk 9D, then by Kath (Hesmondhalgh) and Les (Benton), a couple en route to their daughter's wedding.

Shona (Gunning), an Australian backpacker, enters; she places her bag on bunk 9C then leaves, and Maxwell closes the door.

Maxwell explains the situation to Jorg, Les and Kath argue, and Shona refuses to let Hugo back into her bunk.

"La Couchette", like "Sardines"—the first episode of the previous series—introduces characters gradually, and explores "man's capacity to behave idiotically within a confined space to creepy and comic effect".

[12][13] For comedy critic Bruce Dessau, though the setup was similar, "La Couchette" was "maybe more comic, less sinister, but the denouement is no less nightmare-inducing".

[15][16] These characteristics led to elements typical of Pemberton and Shearsmith's work—characteristics of what The Guardian critic Sam Wollaston calls "Shearsmith'n'Pembertonism"—including "macabre horror, stiff-handling, cadaver spooning" and multiple twists.

[15] Commentators stressed how the characters are generally not particularly likable people,[11][16][17] and one critic observed that the actors are somewhat typecast; "Hesmondhalgh was frumpy but compassionate, while Whitehall played yet another clueless, posh student".

[18] Euan Ferguson identified Roald Dahl and Hitchcock as clear influences,[19] and Ellen E Jones, writing in The Independent, saw a Hitchcockian element in addition to Inside No.

[16] Wollaston described the episode as a mix of Dahl's Tales of the Unexpected, Agatha Christie's Murder on the Orient Express and Chris Donald's Viz.

The writers, she claimed, were able to utilise and subvert viewer expectations of the "strangers on a train" plot tropes, including bad manners, suspense and potential murder.

[18] "La Couchette" was well received by television critics, and was awarded four out of five stars by Gabriel Tate (The Daily Telegraph) and Andrew Billen (The Times).

[18] Jonathan Wright, writing in The Guardian, commended the script of "La Couchette", calling it "a delight, with one line delivered by Jack Whitehall quite possibly the most gloriously tasteless you'll hear on television all year".

[19] Tate said that though he found the revelation at the end of the episode fairly predictable, the "writing and performances were so engaging that it hardly mattered".

[11] Similarly, though Billen considered the setting fairly unoriginal and the characters stereotypical, he said that the writers "scored a laugh every few seconds and then a home run with a savage resolution".

'"[16] Billen commended the cast,[20] and Christine Brandel, writing for entertainment website PopMatters, described Gunning as one of the stand-out guest stars of the second series.

[23] Wollaston, who reviewed the episode for The Guardian, observed that humour generally is extremely personal, and said that he "never really got Shearsmith and Pemberton's stuff".