Jouer l'Arlésienne

This expression is a unique French idiom that translates literally to playing the girl from Arles.  It refers to a person that people speak about all the time, yet that person is never seen, is a "no show."  The person can also be simply described as l'Arlésienne to mean the unseen, the invisible person, the ghost.  You will hear the expression whenever a prominent person is expected somewhere and doesn't turn up.  These days, however, the expression is used more frequently to describe an event or an action that is much talked about and that never materializes or comes to fruition.

You may know that Arles is a city in Camargue, Provence.  Arles is inhabited by Arlésiennes - female residents - and Arlésiens - their male counterparts.  Now, what is it that makes women from Arles so elusive?

The expression isn't actually referring to all women from Arles.  It comes from one specific girl who would have lived in the 19th century.

Origin

L'Arlésienne is a short story, written by French author Alphonse Daudet and first published in his collection Lettres de mon moulin (Letters From My Windmill) in 1869. The (sad) plot is based on a real story which was told to Daudet by writer Frédéric Mistral. Daudet then turned it into a play.  Composer Georges Bizet wrote incidental music for the play's first production in 1871.  The play was a flop, but the music was a success.  And here is the thing: the woman from Arles is the main character but she is never seen on stage.

It is the story of a young peasant who falls in love with a girl from Arles and wants to marry her.  A huge engagement party is organized.  Everyone is waiting for the fiancée but she never shows up.  It turns out she is a seductive charmer, flighty and unfaithful.  The story does not end well: the poor guy sinks into madness and jumps from a window.

So started the myth of the Arlésienne: we keep waiting for her but she never comes - very much like Godot in Samuel Beckett's play Waiting for Godot.  Except that Godot has a name.  The Arlésienne's name remains a mystery.

Examples

On entend beaucoup parler de ce projet mais c'est l'Arlésienne.  Il faut vite le mettre à l'ordre du jour.
This project is much talked about but it has not yet materialised, so we must put it on the agenda very soon.

Depuis la crise financière, la croissance joue à l’Arlésienne avec les pays européens.
Since the financial crisis, growth has been playing hide and seek with European countries.