When I collected my ticket for this evening’s Late Mix concert in Hall Two of The Sage Gateshead, I was somewhat surprised to see it marked as unreserved seating. A computer glitch, I thought, until I walked into the hall and found that the usual rows of seats in this small, in-the-round auditorium had been replaced with café-style tables and chairs. The surprise of this novel seating arrangement immediately set up a relaxed and friendly atmosphere, as people brought drinks in and mingled.

The reason for the cabaret-style was to set the scene for music from 1920s Paris, in a programme that mixed late works by the old guard of Fauré, Ravel and Debussy with a group from the next generation who were collectively known as “Les Six” – Georges Auric, Louis Durey, Arthur Honegger, Darius Milhaud, Francis Poulenc and Germaine Tailleferre. The group seems to have been a somewhat artificial construction, lumped together by an opportunistic journalist more for their friendship than for any deep musical connection, and later egged on by Eric Satie and Jean Cocteau.

Introducing the concert, pianist John Reid warned us that we had to have our savoury course before the “sweets and cake” that were coming up, but Fauré’s Nocturne no. 13 in B minor had a lovely bittersweetness of its own. It was written at the end of Fauré’s life: he had officially retired and had lost his hearing. John Reid’s gentle performance, with his subtle emphasis of the chromatic detail, drew us deep into Fauré’s private world, and the surprisingly boisterous central section made the return of the main theme even more poignant.

By contrast, Ravel’s famous Tzigane for solo violin and piano was given a blazing performance by Andrew Harvey and Reid. Harvey was dressed casually in an open-necked white shirt, and played without music: if he had started to wander around the tables, it would have been no surprise. The improvisatory solo passage that begins the piece was dark and sexy, and the intimacy of the setting only heightened the excitement of the virtuosic madness that followed.

The last of the old-guard composers to be played was Claude Debussy, and cellist Louisa Tuck explained that the creativity and scope for expression makes his Cello Sonata a joy to play. This delight in Debussy’s music came through in her warm performance with Reid, her long-time duet partner, particularly in the characterful pizzicato passages in the second movement, where there was a feeling that both players were simply having fun together.

Milhaud, Honegger and Poulenc are the best known members of “Les Six”, and members of Northern Sinfonia performed chamber music by each of them, alongside Reid’s performance of L’Album des Six a collection of piano miniatures by each composer. On the whole, the contributions of the better-known composers stood out, but Germaine Tailleferre’s Pastorale had a brittle, glittering beauty that I enjoyed immensely.

Milhaud’s String Quartet no. 6 gave a foretaste of the Ravel that was to follow, particularly the slinky viola solo that opens the work, and the gypsy style that underlies the first movement. Some of Milhaud’s string quartets are known for their musical cleverness – the fourteenth and fifteenth can be played together as an octet, and the fifth was written under the influence of Schoenberg’s experimentation. The sixth, dedicated to Poulenc, is sunny and playful, and if tonight’s performance lacked a bit of polish in places, the spirit was there.

One of the best-known works for solo flute is Debussy’s Syrinx, and Honegger’s Danse de la chèvre has the same free-flowing, impressionistic colour. Juliette Bausor gave a mesmerising performance with a wide range of tone, and a lovely sweetness in the upper register. The long flowing runs could easily have become vague, but Bausor’s performance never lost the strong rhythm of the dance.

The last, and sweetest, of the cakes that John Reid had promised us was Poulenc’s delightful Sonata for horn, trumpet and trombone. Peter Francomb, Richard Martin and Stuart Gray took the first movement at a manic pace, whilst maintaining a beautiful chocolatey tone that added depth to the overall frivolity of the piece, particularly in the more sombre passages in the first and second movement. Richard Martin’s bluesy trumpet in the slow second movement was very expressive, providing a thoughtful moment before the glorious chaos of the last movement. Of all the pieces this evening, this little work by Poulenc seemed to sum up the spirit of the age: a consciousness that terrible things have happened and that they will return, but in the meantime, any chance for fun should be firmly seized.