On It's Never Been Like That, their third studio album, France's Phoenix once again give the lie to those who contend the French are incapable of producing rock music of lasting value. Or do they? There's no denying the band's melodically potent, blithe guitar-pop goes down easy, or that songs like ''Sometimes in the Fall'' have a seductive charm that keeps you coming back to them. And few bands of any nationality are capable of transforming a seeming throwaway instrumental like ''North'' into something both artful and compelling. Still, one wonders if the qualities that make Phoenix appealing breeziness, insouciance will ultimately translate into enduring music. Check with us in another 10 years or so.