French horn.

The final phase of the Cite de la Musique was recently inaugurated. The resulting complex is a highly eclectic monument to the dynamism and diversity of musical forms.

The origins of the Cite de la Musique date back to 1982, when the idea of a national complex devoted to musical engagement in various forms (educational, performance and museological) was first proposed. Like Dominique Perrault's National Library (p60), the Cite is the outcome of a lengthy, competition-precipitated gestation and has a similarly ambitious cultural and political remit. In urban design terms, however, there is little similarity between the two intensely gestural Grands Projets. Compared with Perrault's wilfully simple quartet of podium-mounted towers, Portzamparc's wilfully complex accretions of sculptural objects are imbued with an inviting dynamism. Yet just as the most extreme improvisation evolves from the basic disciplines of rhythm and meter, there must be some ordering principles among morphological chaos.

The Cite is in fact two colonies of buildings on the southern edge of the Parc de la Villette, the 35 hectare urban park conceived by Bernard Tschumi in the late 1980s (AR August 1989). The monumental components form two sides of a loosely defined public square and act as gateway to the park beyond. Between the opposing agglomerations of the Cite is a windswept parvis, with a rather forlorn fountain in the middle. On the north side is the cast-iron basilica of the refurbished Grande Halle (AR December 1986) formerly a meat market and now a performance and exhibition venue. The perpetually bustling Avenue Jean-Jaures lies to the south.

Portzamparc originally won the competition for the Cite in 1985, but it soon become clear that such a huge scheme would have to be implemented in phases. The first phase of a new national Conservatoire, on the west side of square, was completed in 1990. Embracing a wide-ranging educational programme of over 50 musical disciplines, it has teaching, performance and residential facilities for 1200 students. Executed with Portzamparc's characteristic (but occasionally questionable) eclecticism, the L-shaped complex is dominated by a sinuous, undulating roof, a monumental version of Tschumi's rippling corrugated canopy skewered at regular intervals by the infamous carmine follies.

Portzamparc's musically inspired career, which began with the Eric Satie Conservatoire in 1981 and was followed by a dance school for the Nanterre Opera (AR November 1989), has now reached a perplexingly idiosyncratic maturity with the Cite de la Musique. The eastern half of the Cite is now also complete and was formally inaugurated earlier this year by President Mitterrand. It contains the performance and museological elements of the Cite's grand design, housed in a fragmented, wedge-shaped building that tapers rakishly to a point on the edge of the square. At the hub of this Cubist collage is a precariously tilted ovoid containing the main public concert hall, which can seat over 1000 concert-goers. Developed in collaboration with Pierre Boulez, seating and stage configurations can be varied to provide appropriate settings for a range of musical performances - from traditional Renaissance recitals to experimental jazz.

The massive ellipse forms the eye of Portzamparc's contrived architectural whirlpool, around which various components of the programme wheel and crash, in a feverish volumetric cacophony. The inelegantly conflicting geometries are lanced by the ramrod fissure of a circulation spine that runs the length of the building. Towards the parvis it metamorphoses into a protective entrance canopy and ultimately collides with a scaled down and slightly apologetic looking folly. Following the beacon-like line of the canopy you move past a succession of randomly dislocated volumes interspersed with fragments of leftover space - on one side, the curiously concertinaed boxes of the music museum (now being fitted out by Franck Hammoutene), on the other, a low slung cafe in the tapering tip. Eventually you reach the immense black box (externally a light blue oval) of the concert hall, surrounded by a dramatically swirling spiral of space. This monumental toplit ambulatory (dubbed 'the conch' alluding to its shape which is also the configuration of the inner ear) is the populist, Decon equivalent of Garnier's majestic salons and staircases at L'Opera, where the audiences can preen and promenade before, between and after performances. During the day, however, minus the seething crowds of music-loving flaneurs, the cavernous, ice blue interior looks decidedly surreal and woebegone.

The rear of the building is given over to a curved strip of cellular offices, rehearsal rooms and student accommodation, some with views into the ambulatory. At lower level is a smaller amphitheatre housing an impressive Baroque organ. Portzamparc's dissection and fragmentation of space does have the advantage of providing total acoustic separation, in a building with many competing aural requirements. It is also intended to create a kind of sanitised and internalised version of Paris' nougaty urban texture, with sequences of streets, squares and the odd cul-de-sac. Yet the ironic, heaped-on arbitrariness of the gestures can wear thin - here a lilac wall, there a vaguely guitar-shaped window- leaving the visitor gasping for some clarity and simplicity, some semblance of intelligible continuo to contain the maniacal extemporising.

As with Perrault's library, it is too early to predict the true effectiveness of Paris's new Cite. Energetic programmes of regular monthly events have been planned and much will depend on critical reaction to the acoustic performance of the showpiece concert hall. But it is clear that Portzamparc has made a highly theatrical stage set of a building, which for all its quirky bricolage has the potential to accommodate both the internal drama of performance and the external drama of the city.