As fans trooped into Bercy stadium on Tuesday night, the Breton flag - a huge black and white symbol - unfurled itself against the night sky. Meanwhile, on stage down below a host of Celtic stars were warming up for their performance. The line-up at Bercy featured none of the new generation of Celtic chart-toppers (such as 'folk/rap' duo Manau), but an army of the Old Guard, the Breton veterans who have been performing their Celtic heritage for the past twenty or thirty years. Real folk musicians such as Alan Stivell, Dan Ar Braz, Gilles Servat and Tri Yann who follow in the footsteps of the old Celtic bard Glenmor and carry on the ancient tradition which has been handed down orally through the mists of time. The concert at Bercy was to be an evening of real Celtic folk music, the kind which revolves around traditional instruments - the bagpipes, the biniou, the bombarde, the fiddle, the Celtic harp and the bouzouki (instruments which are common to Breton musicians, but also to their Celtic cousins in Galicia, Ireland, Scotland and Wales).

Gilles Servat was the first to take to the stage beneath the Breton flags. "We're all going to sing in Breton tonight," he announced to the audience at the start of his set, proving that he had lost none of his famous militancy. Servat, who rose to fame in the 70's as a committed protest singer, has immersed himself in Brittany's ideology, making the region's language and its customs his own. (Servat was actually born outside Brittany, in Tarbes, but his family trace their roots back to Nantes). Servat scored a whole string of folk hits on the French music scene in the 70's with hits such as "L'hirondelle", "Je dors en Bretagne ce soir" and "La Blanche Hermine" - a song which Servat recently re-released in protest at the fact that the National Front were singing it at their political meetings. Throughout his career Servat has shown a passionate interest in Ireland and he paid tribute to his Celtic cousins on Tuesday night, singing a French adaptation of the Pogues' classic "Dirty Old Town".

The next to arrive in the shadow of the gigantic triskèles (the cross - traditional symbol of Brittany), was the legendary Celtic folk star Alan Stivell, the man responsible for exporting Breton music outside regional frontiers. The tall, thin figure calmly seated himself at his instrument - his traditional golden harp which has been reworked with a hint of futuristic design - and launched into two songs about peace in Ireland. Needless to say, Stivell's entire set was sung in Breton and he did not forget to pay tribute to the Goadec sisters (Brittany's traditional music divas), singing a cover of "La mémoire de l'humain" with full percussion backing. Stivell was the first French folk musician to come up with the idea of fusing traditional Breton music with electro sounds. And, true to form, Stivell has kept his pioneering spirit today - his latest album "1 Douar" fuses Celtic folk, techno and rock influences and features guest vocals by world music stars such as Khaled and Youssou N'Dour.

The award for best folkloric costume had to go to the exuberant Breton trio Tri Yann. Tri Yann (literally the three 'Johns') leapt on stage sporting kilts, breeches and cheeky little hats decorated with bright orange pompoms. The three minstrels from Nantes proceeded to launch into their innovative brand of medieval folk-rock, interspersing their songs with a few energetic gavottes. The crowd went wild as Tri Yann rolled out their best-known hits, playing their old classics "Dans les prisons de Nantes" and "la Jument de Michao". And the trio brought the house down when they launched into a rendition of the famous Breton folk hymn "Bro goz ma zadou" (Land of My Ancestors) - the one 'pacifist' folk legend which does not involve blood and battle!

The award for assembling the maximum number of musicians on stage undoubtedly went to Dan Ar Braz and the Héritage des Celtes. The famous 'Bagad de Kemper' united fifty musicians at Bercy, bagpipe-players and bombarde-players marching around the stage led by a troop of traditional Celtic drummers. Up until Dan Ar Braz's set the evening had been resolutely masculine, but the famous folk guitarist from Lorient had the bright idea of inviting Scottish singer Karen Matheson up on stage with him. A whole host of surprises followed, Dan Ar Braz going on to perform with Welsh star Michael Jones and French singer/songwriter Jean-Jacques Goldman. Dan Ar Braz also extended a warm welcome to his Celtic cousins from Galicia, giving the stage over to the Spanish soloist Carlos Nuñez.

But the highlight of the evening, the moment the crowd was really waiting for, was the on-stage reunion of Dan Ar Braz and Alan Stivell. Dan Ar Braz and Stivell had been old friends on the folk scene for many long years, but the Celtic stars had had a rather public falling-out halfway through their careers. Much to the audience's delight at Bercy, Dan Ar Braz and Alan Stivell took to the stage together for a grand finale, performing an extract from 'La Symphonie celtique'. The audience duly burst into rapturous applause, dancing a round of celebratory jigs to mark the happy occasion.

Pascale Hamon