Trojan horse.

Jean-Michel Wilmotte is admired for a series of discreet insertions into existing buildings and his quiet design of the foyer underneath the Louvre Pyramid is a fine example of this. His architectural language is one of enriched Modernism and he characteristically makes sumptuous use of materials -- stone, metal, and glass -- and avoids most kinds of decoration.

Wilmotte has had a hand in designing the new interior of the Richelieu wing of the Grand Louvre, the architect in charge being I.M.Pei. Wrested from the hands of the French Finance Ministry (dispatched to the Chemetov and Huidobro building in Bercy on the eastern side of Paris), the wing has added another 165 galleries to the already mammoth museum.

This is the second phase of the government's scheme to create a vast cultural anchor in the centre of Paris. Parts of the palace and the gardens have not yet been restored and the Solferino bridge is still to be built over the Seine. But when work has finished, the Louvre, with its famous pyramid, will no doubt be the largest museum of art in the world, and certainly one of the most opulent.

Despite the aroma of the corporate that hangs in the air, the Louvre will be -- is -- an impressive symbol of Gallic pride and a honeypot for millions of visitors. Wilmotte's austere talents have been employed on the design of several of the more commercial parts of the Grand Louvre scheme. In the Richelieu, as well as re-planning the galleries on the first floor, and designing the showcases and furniture throughout the wing, he has designed the severe new Cafe Richelieu on the first floor. Here, as elsewhere in the scheme, Wilmotte has had to reconcile his insistence on timelessness in design with the historical clamour of the building. He has done so with particular suppleness.

The Cafe Richelieu, overlooking the Cour Napoleon, occupies the former office of the Minister of Finance and the ante-rooms opening out on to open terraces on either side. In designing it, Wilmotte's point of departure was his own passion for modern art, a subversive one in these Second Empire, antiquity-laden surroundings. Having long supported the idea that architects should provide space for artists, he spotted an opportunity to introduce modern works of art into the Louvre. The sacrilege was not as great as it seemed. Apart from the obvious intrusions by modern architecture, there was a painterly precedent: the ceiling by Braque for the Sully Pavilion installed in 1953.

It took Wilmotte some time to persuade his clients of the force of his idea, but once permission had been given and the design done, the scheme was completed in a record two months.

The Braque ceiling, which provided both a justification and a source of inspiration for Wilmotte's scheme, led to the discovery of a curious ghostly counterpart. In stripping down the ceiling of the Minister's office, a nineteenth-century Baroque decorative scheme, washed by delicate shades of blue, gradually emerged. In the end, this inspired decoration of the new cafe. The predominant colour has been intensified and used as a decorative background in the principal room and the Salle Raynaud to the west, covering old panelling and doors, and unifying the various elements. To an English eye, the colour seems particularly French (though Wilmotte calls it Royal Air Force); a dark version of the French blue one associates with the thin doors of nineteenth-century Parisian apartments. Against this flat colour, that of the the wood used for floor and furniture is rich.

The furniture designed by Wilmotte is plain, handsome and distinctly covetable -- particularly the chairs. Well-proportioned and solidly articulated, they are made of walnut, steel and blue leather. Tables are of walnut and steel; a bar is composed of a slab of glass resting on a base of sanded aluminum. Light pours into these dark-coloured caves of rooms through high windows, framing a view of the Pyramid outside.

Wilmotte's artistic collaborators were chosen by him for their sensitivity to the site and their ability to make the most minimal scratches on the patina of the old. The Salle Raynaud, giving onto the Terrasse Turgot, is perhaps the more successful of the two ante-rooms. Named after the artist, Jean-Pierre Raynaud, it is crowned by a suspended vault of white faience tiles bearing a radiation symbol. Conceived as a futuristic tribute to Fra Angelico's Annunciation, in which a blue constellation floats over Virgin and angel, this appears to float in space. Natural and artificial light is reflected off the vault, turning it into a source of light.

On the east side, in the Salle Buren next to the Terrasse Colbert, Daniel Buren has been given a free hand with white paint. With it he has created a swathe of long stripes of white which travel across the surfaces of the room, blue or otherwise: floor, walls, window and ceiling. Even the furniture and crockery have not escaped this Rileyesque striation. Against the sombre walls, the stripes appear as strobes of light.

Elsewhere, the faces of the statues around the Cour Napoleon have been given enigmatic, human substance by Francis Giacobetti, whose sepiatinted photographs of them adorn the cafe's walls, while Cesar's composition of compressed car parts stands beneath the Baroque ceiling, on the axis of the pyramid.