I had heard a lot of negative things about it but, while falling far short of his best efforts, the film is not quite Chabrol's nadir either – as many would have it; on the other hand, it has been likened by some to the work of Luis Bunuel (due to its fantasy/surreal elements which, however, bafflingly draw attention to themselves by being bathed in a soft glow!). Still, the overall treatment is way too farcical to have the desired satirical effect (in fact, this more readily approximates the style of a Fellini or Marco Ferreri!); ultimately, the film's main flaw is the lack of a proper plot – conversely, a definite asset emerges to be Manuel De Sica's score, which is alternately emphatic and wistful but always haunting.
I, for one, was particularly drawn to it by virtue of a star-studded cast; this factor, however, proved misleading since most are given thankless roles: worst of all in this regard were Charles Aznavour as a doctor and Curt Jurgens as a jeweler (incidentally, an uncredited Chabrol even gives himself what amounts to a walk-on part). Typically, the women are numerous and lovely: Stephane Audran (delightful as ever in her last – and most histrionic – leading role for her director husband, showing off her statuesque body despite being 43, and also seen having a romp in a Volkswagen with her legs stretching out of its top!), Sydne Rome (as her impetuous niece), Ann-Margret (as Audran's romantic rival, called Charlie Minerva, involved with both her husband and lover[!]) and Sybil Danning (as Audran's lover's secretary); the odd one out in this company is Maria Schell, who is decidedly embarrassing as a wacky maid: unaccountably developing a hankering for a male doctor, she throws herself out the window in order to be put into his care – later, when the protagonists relocate to the country and her room is destroyed by a torrential downpour, she tells her employers: "You don't need a maid but an exorcist!"
The men in the cast are no less notable: Bruce Dern (as an American poet living in Paris craving a literary prize that eventually goes to a local writer – whose wife Audran fantasizes doing a gratuitous nude scene in a theater and himself imagines having a foursome with Rome, Ann-Margret and Danning, until Audran turns up to castrate his gigantic erection!), Jean-Pierre Cassel (his third and last film with Audran, here playing her lover and Dern's publisher, following Chabrol's own much superior THE BREACH  and Bunuel's masterpiece THE DISCREET CHARM OF THE BOURGEOISIE ) and Tomas Milian (as a Chaplinesque detective, forever having the biscuits he is dunking melt in his coffee, whom Audran appoints to spy on her lover!).
P.S.: An interesting coincidence relating to Dern and TWIST is that, in the same year, he starred in a film by Alfred Hitchcock i.e. FAMILY PLOT (1976) and this, made by his French counterpart Chabrol (not to mention the co-author of the first-ever critical study on the Master Of Suspense's work)!