The new Pompidou-Metz museum opened yesterday in a small Cathedral city in the west of France in a ceremony attended by Nicolas Sarkozy. At first glance, the €86m new museum designed by Shigeru Ban and Jean de Gastines appears to be more roof than anything else, but the metallic volumes that puncture the draping canvas structure are the 85m long galleries, directed towards the city's landmarks and most picturesque views. The Forum, the vast open space on the ground floor through which all internal circulation takes place, which will eventually be used like Tate Modern's Turbine hall for commissioned works of art.

The roof's bespoke and complex geometries were created using Arup's form-finding software but inspired as the story goes, by a woven bamboo Chinese hat which Ban took along to meetings. Much effort was made to ensure the roof – with no straight lines, double-curvature engineering on beams and tesselating layers of hexagons – appeared as natural and elegant as possible. Quite the opposite of the original "inside out" approach of Rogers & Piano's seminal work in Paris.

The Pompidou-Metz is first branch of the Pompidou to exist outside of Paris and it operates on model that the city who hosts the museum will broadly pay ofr it and enjoy the related "Bilbao-effect" of cultural tourism. The museum has no collection of its own, the inaugural exhibition, starting this week, is called "Masterpieces?" Beatrice Galilee