Marseille-based Watcha Clan are the latest exponents of the Afro-French crossover groove style that has previously spawned bands like Lo'Jo, their music intended to surmount cultural divides through the judicious blending of beats and diverse influences. "This is Radio Berber!" announces singer Sista K, quickly correcting herself, "Radio Babel!"; but she's not wrong either way, there being more than a little of the hypnotic Berber desert-blues vibe about Watcha Clan's music, which reached Britain for the first time in front of a small but enthusiastic audience at east London's Rich Mix.

The show opens with sampler/keyboardist Suprem Clem, robed and hooded in bright white folds, looping vocal samples into a groove, with bassist Matt Labesse adding lower-end propulsion via a solid electric double-bass. The rest of the band joins in for the loping, head-nodding groove of "With Or Without the Wall", Labesse switching to guitar while the energetic Nassim takes over the bottom end with his gumbri, a North African bass whose throbbing, sandy tone gives the music a distinctive gritty texture. "Nobody owns the land," sings Sista K, heralding the night's recurring theme. "The land is free, so why walls?"

This attitude of cultural fellowship is most directly expressed, though, through the way the band ingeniously blend musical influences. There are traces of Latin American cumbia, Caribbean reggae and Balkan Gypsy music in both the feisty, Gogol Bordello-esque "Tchiribim" and "Balkan Qoulou", for which Suprem Clem straps on an accordion, while "Gypsy Dust" is built around samples of Fanfare Ciocarlia, the ebullient Romany brass band. And the addition of the breathy duduk reed of Merlin Shepherd casts a powerful Middle Eastern spell over a soulful version of "Im Nin'Alu", the Hebrew poem that was widely sampled in the late-Eighties version by Ofra Haza.

The audience are swept up in the infectious rhythms of songs like "Hasnaduro", "Goumari" and the self-explanatory "Fever Is Rising", with various band members jumping offstage to lead the dance in person. By evening's end, Olympique de Marseille may be out of the European Cup, but a small corner of the East End has been won over in recompense.