In Henri Dutilleux's Mystère d l'instante for 24 strings, cimbalom and percussion it is easy to dwell on the cimbalom as a freak in the concert hall, but Hungarian Xavér Ferenc Szabó introduced it to the symphony orchestra in the 19th century when it was essentially gypsy folk music instrument and later Zoltán Kodály used it in the 20th century in his symphonic music. The instrument is far older, a sort of piano before the keyboard and related mechanism were invented, probably used in the middle and near east in ancient times, coming west not too much later. One music historian describes its sound "rather like a piano that has taken its clothes off!" That gives the cimbalom an unfair primitive appearance, its construction no doubt demands as much care and refined techniques as any to sound so convincing next to the usual bowed strings. It no doubt strikes the ears of a modern audience accustomed to symphonic music as antique or near eastern, at least exotic, but I don't think Dutilleux intended to make any such avant-garde statement for its own sake, and the piece certainly doesn't have the form of a concerto. Rather I think he wanted a windless orchestra, a study in strings, without even much plucking, mostly bowing and tapping, if we can think of the percussion instruments as two dimensional strings.
In the decade after the second world war, Paris and London, in addition to the big national companies, supported a myriad of small and prolific ballet companies. One of these was Boris Kochno's Ballets des Champs-Elysées. Kochno had been Serge Diaghelev's secretary in the Ballets Russes days, so in a way it was he who inherited the Ballets Russes tradition in Europe while Colonel de Basil and Serge Denham's two respective Ballets Russes spin-offs were still touring the US and Australia. Kochno, as artistic director, founded the company with writer Jean Cocteau, and dancer and choreographer Roland Petit, who had trained in the Paris Opera Ballet School and danced in the corps de ballet until the Liberation. In 1948 Petit started his own small company, the Ballets de Paris, which only lasted a few years, but managed to cause great excitement in Paris and travelled well to London. Indeed, he worked with Margot Fontaine several times. We don't often get to see his ballets nowadays (though there are also a great many other modern ballets from those years, even some of Michel Fokine's, that don't get much air either), but the Paris Opera Ballet is currently showing three of Petit's short pieces, Le Rendez-vous (1945), Le Loup (1953) and Le Jeune Homme et La Mort (1946) which have been in the national company's repertoire since 1992, 1975 and 1990 respectively.