Elemental synthesis: set in rolling countryside, this museum devoted to the study of Celtic civilisation explores a modern sensibility of abstraction and asceticism.

Set in rolling countryside, this museum devoted to the study of Celtic civilisation explores a modern sensibility of abstraction and asceticism.

Set amid rolling French countryside, the new museum of Celtic Civilisation at Mont Beuvray merges almost imperceptibly with its surroundings, From a distance it appears as a horizontal sliver in lush landscape, composed of crisply articulated planes of marble, glass and fair-faced concrete. Housing relics from the pre-Roman era of Celtic civilisation, the new museum has an educational and cultural remit similar to that of Chaix and Morel's archaeological museum at Vienne (p61), and explores a comparable sensibility of abstraction, transparency and asceticism.

The two-storey building occupies a gently sloping site on the edge of a forest, with views over farmland to the south. The patti is relatively simple, consisting of an L-shaped plan carefully incised into the slope. The main entrance and museum level is elevated on a modern version of the traditional rusticated base, a plinth clad in rough undressed stone in the manner of surrounding farm buildings. Above the plinth rise external walls of finely jointed marble and fair-faced concrete. Set within this opaque carapace is the transparent glass box of the main exhibition space, which is only partially visible from the outside. An overhanging flat roof, punctuated by the jagged.profile of saw-toothed rooflights, unites the distinctly Miesian composition.

The short part of the L thrusts out down the slope to form a wing containing the entrance, cafeteria and space for exhibitions. To the rear of the wing are the museum's offices. The long part of the L houses the main exhibition space, an elegantly proportioned box penetrated by a mezzanine level above. Once inside, the relationship of the layered walls of glass and marble becomes clear. Daylight diffuses through the gap between the two planes, softly illuminating the exhibits and animating the space. Light is also admitted through the quasi-industrial saw-toothed rooflights, which are infilled with milkily translucent glazing. A central circulation spine leads visitors through an enfilade of exhibition areas enclosed and defined by vertical planes of fairfaced concrete. These internal walls, one-storey high, are positioned at right angles to the spine. Austere and elemental, the raw concrete planes support cylindrical steel columns that make up the building's structure. This simple yet ingenious combined system of walls and columns liberates space at mezzanine level, while providing intimacy and enclosure on the ground floor. Rows of minimal glass cases containing relics, artefacts and models are arranged in each display area, where the stone floors of the circulation spine give way to polished timber and dark grey marble. In some instances, the floor disappears to reveal the remnants of actual excavations. Signage is equally elegant - explanatory texts are stencilled on to glass panels, which are either mounted on the concrete walls or held in free-standing steel frames. At mezzanine level, lightweight panels of cotton scrim are stretched taut over timber frames, forming full-height screens for audio-visual presentations on the artefacts below. Both this building and Chaix and Morel's archaeology museum are essentially beautiful, neutral containers. Through a finely judged synthesis of materials and light, both echo the elemental potency of the exhibits they house.