French dressing.

In Paris, another of the venerable French museums has been renovated and reorganized with sensitivity and respect for historical layering.

Restoration and modernization of the Musee Nationale des Techniques, popularly known as the Musee des Arts & Metiers, has been completed to general acclaim. The museum, which is devoted to the artefacts of the industrial revolution - clocks, ships, planes, engines, industrial devices - has a collection of about 80 000 objects and 15 000 technical drawings and plates.

As part of the great pantheon of grand French museums to have been renovated, it is hugely popular with the general and professional public. The Turin-based architect, appointed to carry out the work under Francois Mitterrand's presidential reign, was Andrea Bruno who is known for his sensitive work on historic buildings, notably on Rivoli castle near Turin. In Paris, Bruno worked in association with XY Architecture.

The museum is part of the Conservatoire Nationale des Arts & Metiers, an august institution occupying the grounds and buildings of the early medieval Abbaye de Saint Martin des Champs in the third arrondissement (a stone's throw from the Pompidou Centre). The Revolution had dissolved the abbey's power, and the site was occupied first by a school, then by an arms factory and eventually assigned in 1798 to the Conservatoire. Apart from the church (with its twelfth-century choir, thirteenth-century nave and later additions) and the spectacular vaulted medieval refectory (now a library), the old buildings were reconstructed in the eighteenth century, restored and enlarged between 1845 and 1897 under the direction of Leon Vaudoyer, then further restored by Henri Detroux on the eve of the First World War. In 1880, at a time when enthusiasm for industrial invention was at its height, the museum was reorganized and the deconsecrated church nave converted into a magnificent space for exhibiting machines. Bruno's stra tegy was to work with, rather than against, the complex superimposition of historical layers and to establish a clear distinction between the historical and the modern. In general, his touch has been a light one.

The museum occupies roughly half a long rectangular block at right angles to the church, with the rest of the building to the north of the grand central staircase being inhabited by the various offices of the Conservatoire. There are two floors, with grand windows, beneath an attic. Bruno has conserved the original volumes and his modern additions of lifts (in the internal courtyard), stairs, a cafe, shop and lavatories impinge lightly on the existing structure. The church has been restored by Bernard Fonquernie, architect for the Monuments Historiques de France, and retained as an exhibition space. A somewhat curious decision by the client body to appoint another architect to design the exhibition in the nave has resulted in the exuberant steel and glass viewing structure by Francois Deslaugiers.

Much of Bruno's structural work is invisible. While the Monuments Historiques restored the monumental staircase, decorative plasterwork and glazing, he strengthened constituent parts of the fabric to make it capable of accommodating large numbers of people and weighty showcases. For example, in the attic, a composite floor supported by a concrete rim was installed to conceal services. Elsewhere, concrete replaces rotten wood floors, window frames have been repaired, and a mezzanine was installed on the ground floor to expand exhibition space.

On the ground floor, services controlled from centres at the corners of the wings are contained in metal ducting running overhead and designed to evoke the spirit of nineteenth-century industrial design. Designed in the same spirit and similarly transformed into a modern idiom, Bruno's display cases with wood or brass frames are sparely designed and traditional in feeling. Attic collections have been dusted off in new cases which line the walls so that you walk between them under the roof beams.

The seductive power of this museum consists first of all in the palpable sense of history present in the site, in the overlaying of architectural layers put down over centuries and revealed by degree and the architects' clever juxtapositions. More immediately, there is the excitement of appreciating the invention and imagination of the industrial revolution, felt most profoundly in the nave of the church where the modern artefacts are juxtaposed with the medieval fabric.