Parisian promenade.

A historic urban railway viaduct has been imaginatively revitalised to provide an elevated linear park and upmarket shop and office units.

Since he set up practice in the late 1970s, Patrick Berger has carved out an individual niche for himself in contemporary French architecture. The deceptive simplicity of his few executed projects belies a highly wrought attention to the inherent nature of materials and a keen sense of time and place -- qualities notable in his contribution to the Paris-Citroen-Cevennes park (1985-93) and his Rennes school of architecture (1986-90). It was on the strength of these distinctive successes that the City of Paris commissioned Berger in 1988 to work out a strategy and detailed design brief for the transformation of the disused Bastille railway viaduct.

Conceived in 1858 as part of Napoleon III and Haussmann's Paris Improvements, the viaduct carried a section of spur-line off the Petite Ceinture (the railway encircling the city within the fortifications) and was built to provide Parisians with direct rail de la Bastille out to the chateau, town and new park at the Bois de Vincennes on the eastern flank of the capital, landscaped in tandem with the Bois de Boulogne to the west.

The Bastille terminus, the viaduct and the stretch of embankment linking it to the Gare de Reuilly were closed in 1969, but the SNCF continued to make use of the Reuilly goods yard and the remainder of the spur until the mid-1980s. Striding across the 12th arrondissement townscape to the north-east of the Rue de Lyon and the Avenue Daumesnil, the Bastille viaduct had fallen into the forlorn anonymity typical of such redundant infra-structures -- its arches occupied by a humdrum mix of small businesses, workshops, cafes, garages and the like, which had progressively obscured the fine lines and materials of the structure: red brick spandrels setting off the stonework of the vaults, piers and arches, finished off with a boldly corbelled stone cornice and blocking course.

Ever since the 1969 closure, the City of Paris's planning department had been understandably eager to re-develop the spur-line within the city limits, and in particular the 13-hectare Reuilly goods yard site and the three hectares of sidings at the Petite Ceinture junction, as part of the urban renewal plan for the east end of the capital. But the SNCF's continuing need for the station and sidings postponed any concrete development for a long time. During the mid-1970s, complete clearance of the viaduct and the embankment was envisaged. More detailed analysis revealed that such an approach was liable-to create more problems than it would solve. The backsides of the buildings , abutting the viaduct would have been exposed all along Rue de Lyon and Avenue Daumesnil, leaving a bald jumble of gable ends, yards, sheds and bits of wasteland confronting Haussmannian and turn-of-the-century apartment blocks on the other side of the tree-lined road.

Following the 1978-1979 revision of the city's redevelopment policy and the creation of the Atelier Parisien d'Urbanisme -- APUR, the city's urban design agency -- a rather more sensitive approach to the renewal of the Parisian fabric was adopted. Moreover, in 1981-1982, the newly elected Socialist government's plan for a 1989 universal exhibition persuaded the SNCF to rationalise its rail network in the capital and to negotiate the sale of the Bastille line to the city. Although plans for the exhibition proved abortive, President Mitterrand launched his Grands Projets -- among them the new Opera to be built on the site of the Bastille terminus (for which Carlos Ott won the competition in 1983 (AR December 1983).

APUR, whose urban design policy for the east end of Paris had attached great importance to the `greening of the city', presented a new set of proposals for turning the Bastille line into an urban asset, retaining the viaduct, embankment and cuttings to provide a promenade plantee or linear pedestrian park, running from the rear of the new Opera right across the 12th arrondissement to the Bois de Vincennes, linking the park spaces planned for housing projects on the station and siding sites. APUR's plans for the Bastille line were approved by the City Council in 1987, when purchase of the SNCF land was completed. To provide access from street level to the elevated section of the promenade and to enhance its attraction, a number of small sites adjoining the viaduct and embankment were also acquired.

Working within APUR's master plan, Patrick Berger has approached the rehabilitation and appropriate adaptation of the viaduct with commendable restraint and respect for the original structure. He has taken his cue from an 1858 L'Illustration article, which describes the viaduct as being designed to have open arches faced in brick with stone dressings, in a style of which `the nearby Place Royale (Place des Vosges) offers such an elegant specimen', with the columns of the cast-iron bridges over the cross-streets exactly aligned on the trees bounding the Avenue.

The premises created within the railway arches are designed for upmarket tenants, attracted by the upgrading -- not to say gentrification -- of the area stimulated by the Bastille Opera. So as to curb any latent tendencies to commercial cacophony that might compromise the restored architectural integrity of the viaduct, Berger has imposed a strict specification for the design of new shop fronts within the former railway arches. To maintain the coherence of reinstated stone piers and arches, all shop fronts are recessed, with glazing to both elevations contained by an austerely taut timber frame which preserves something of the former transparency of the arcade. Suspended pairs of cable-tensioned translucent blinds may be inscribed with the name of the resident shop or business. Slung from the stone vault on stainless steel hangers, slightly bowed timber "ransoms, which house lighting and fixings for external door and window frames, express inserted mezzanine floors.

Inside, the quality of the stone vaults is fully exposed. Tenants are strictly forbidden from installing any extraneous fixtures or fittings and, to date, designers of shop-fits have complied with this requirement. The one exception to the rule is Jean-Michel Wilmotte, who has been allowed to open up passages through piers and to insert glazed panels in floors on the mezzanine level in his conversion of five adjacent railway arches, to create new show rooms for the government-sponsored furniture design agency, VIA.

At the Reuilly end, the embankment beneath the promenade has been rebuilt to echo the rhythm of the bays in the restored viaduct, with a row of shops flanked and bridged at each end by new blocks of flats. Philippe Mathieux is responsible for the landscaping of the promenade, which now runs from the back of the Bastille Opera to the recently opened park at Reuilly. Incident is provided along the route by a garden created by Andreas Christo-Foroux on the roof of a car-park.

Now just over a kilometre in length, the promenade plantee has proved a great success with Parisians and tourists alike. Aloof from traffic noise and exhaust fumes, it offers a series of unexpected views -- from glimpses of the city's intimate anatomy in close-up, to plunging urban vistas through branches of the trees bounding the road below. Moreover, not only does this new linear pedestrian park revive the device of the elevated promenade (provided by the seventeenth and eighteenth century Paris boulevards on the city ramparts, and by the raised pavements of Bath and Bristol) but it demonstrates, too, that CIAM notions of vehicular and pedestrian traffic separation were not totally misguided.