Raymond Fonsèque was a trombonist, tubist, arranger and bandleader who spent his working life in French traditional jazz, ragtime and swing. He was born in Paris on November 27, 1930, led his own Original Jazz Band and a group called the Hot Four Nouvelle-Orléans, and received the Académie du Jazz's Prix Sidney Bechet in 1981. He passed away on November 19, 2011, in Évreux. Away from the bandstand he spent years on a tuning system of his own, a "super tempérament" with 24 notes to the octave.

He came from a family of musicians: according to French Wikipedia his mother was a classical pianist, his father an opera singer and one of his brothers a drummer. He studied piano and cello formally, took harmony classes at the Bordeaux conservatoire during the war years and sang in a vocal ensemble that performed in churches after he returned to Paris in 1944. At seventeen he switched to trombone, studying with André Hodeir. His interest in New Orleans jazz grew through the second half of the 1940s, and he worked with Claude Luter and his Lorientais, the clarinettist Robert Mavounzy, the pianist Jack Diéval and Christian Bellest. In 1948 he was a co-founder of the Hot Club de la Vallée de Chevreuse, and in 1949 he turned professional with the pianist Christian Chevallier, who was playing at La Coupole in Biarritz.

The early 1950s brought work with André Réwéliotty, Yannick Singéry and Don Byas, and military service in 1950 and 1951 at Courbevoie, where he played tuba in the 93rd Infantry Regiment. He then took tuba and trombone lessons at the Paris Conservatoire in the class of Paul Bernard, working on bass trombone. Through the decade he played with Maxim Saury, Nelson Williams and the group Metro Jazz with Michel Attenoux and Gérard Badini, in which he appeared with Peanuts Holland and Lil Armstrong at the Salle Pleyel. He toured Germany with Armand Gordon's Dixie Pals, played in a four-trombone ensemble with the pianist André Persiany, worked in the orchestra of Jacques Hélian and, according to the German and French Wikipedia articles, with Sidney Bechet, Big Bill Broonzy, Mezz Mezzrow, Albert Nicholas, Bill Coleman, Benny Waters, Cat Anderson and Kenny Clarke. English Wikipedia names Claude Bolling and Claude Luter among the French bandleaders he played for. One recording from the period is documented: he plays trombone on André Réwéliotty's Vogue EP of previously unreleased Sidney Bechet compositions, recorded in Paris on June 23 and July 1, 1959.

In 1961 he recorded under his own name with his group the Washboard Five, with Pierre Braslavsky on soprano saxophone, René Gervat on clarinet, Jacques Chrétien on cornet and trumpet, Jean Abusch on guitar and Teddy Hocquemiller on washboard, according to French Wikipedia. He was one of the trombonists in the big band of Jacques Denjean: the 10-inch album Jazz (Polydor), recorded in Paris on June 28 and 29, 1962, lists him in a trombone section with Françcois Guin, Marc Steckar and Michel Camicas, behind a band that also held Ivan Jullien as arranger and trumpeter, Jean-Louis Chautemps on alto saxophone and Gérard Badini on tenor. The Denjean band played the Antibes and Juan-les-Pins festival, and Fonsèque also belonged to a revived group called The 4 Trombones Incorporated, with Charles Orieux, Michel Camicas and Guin, which played the Paris Olympia and Juan-les-Pins in 1964. In 1965 he became president of the Jazz Club de France, in 1966 he led various bands at the Caveau de la Huchette, and from 1968 he played in the orchestra of the Folies Bergère.

His own bands made their records in the 1970s. Ambiance Ragtime au Caveau de la Huchette (Président, 1970) was credited to the Raymond Fonsèque Original Band, with Fonsèque as arranger, conductor and trombonist in a front line with the trumpeter Marcel Bornstein, the clarinettist and soprano saxophonist André Villeger and the trombonist and pianist Didier Hussenot, over a banjo, a bass saxophone and a washboard. In 1971 the same band recorded with the American trumpeter Bill Coleman in Montmagny (June 4) and Taverny (September 26) for the National label, and a second Coleman album, Bill and the Boys (Concert Hall, 1972), lists Fonsèque on trombone and as conductor. He is also on trombone on Au "Petit Journal" (National, 1971) by Jazz Fouchtra, and French Wikipedia adds the Pop Corn Brass Band and the High Society Jazz Band to the groups of the decade. In 1979 he toured with the trumpeter Cat Anderson; a live set from April 27, 1979 at La Celle-Saint-Cloud, with Daniel Huck on saxophone and Philippe Baudoin on piano, was issued by Milan in 1992 as Ellington Moods.

From 1981 to 1992 he taught trombone and tuba in several conservatoires and formed big bands with his students. His tuning work began in 1983, when he devised a 24-note system, patented a keyboard with 24 distinct notes per octave and built a prototype that November. A paper on the method appeared in the Bulletin du G.A.M. in 1986, and French Wikipedia says he presented it that year at the Faculté des sciences de Paris and to the Groupe d'Acoustique Musicale of Paris VI. His own bands kept recording: the LP Fonsèque & Co Jazz-Band (RFJB, 1986), a CD-R made in December 2000, and, in 2002, a Montbard festival DVD on which he is credited as film director and camera operator with Jean Fauve. In 1993 he published a magazine, Jazz Dixie Swing: du ragtime au big band. A video of his quartet at Marciac in 2007 is online, and he passed away in Évreux on November 19, 2011.

Fonsèque belonged to the New Orleans revival and the ragtime and swing-era branch of French jazz, and the records that carry his name use its instruments: banjo, washboard, bass saxophone and tuba under a trumpet, clarinet and trombone front line. Most of his documented credits are as an ensemble and section trombonist, in dance bands, big bands and trad groups. No interview in which he names his influences was found, so this section sticks to the repertoire and the credits: ragtime and New Orleans titles such as "Texas Moaner", "Chattanooga Stomp", "Ballin' the Jack" and "Lassus Trombone", Duke Ellington pieces ("The Mooche", "Black and Tan Fantasy") on the 1986 LP and on Ellington Moods, and original titles in French on the 2000 CD-R. He also worked as a teacher, an arranger and an organiser, and the super tempérament, a 24-note scale that allows major thirds to be played in just intonation, shows a second, theoretical side to his work.