Metropolis now

Berlin's latest addition to its "federal belt" of showpiece government buildings is the Paul-Löbe-Haus. This is an 81,000 m2 office block consisting of eight wings, each joined to a glazed atrium (imagine four people using eight stubby oars to propel a boat and you will have an idea of the plan view).

The office will house what the Germans regard as the "engine room" of the republic: the committees of the country's parliament, which help to formulate the policies and laws discussed in the adjacent Reichstag.

It is also a work of heavily underlined symbolism. First, there is the familiar connection between democratic and physical transparency. Inside the atrium, each block ends in a semi-circular glazed rotunda where the committees will hold their meetings in full view of passing voters. Project architect Karin Melcher comments: "The use of glass and the circular form of the meeting rooms give the structure transparency and democracy."

Then there is the more specific symbolism that relates to Germany and Berlin. Stephan Braunfels Architekten's design rests on the inside bend of the River Spree. On the other side is its sister structure, the Marie-Elisabeth Lüders library, which is due for completion in 2004. The structures were conceived as part of a single £270m project to be placed on a site that was split by the Berlin Wall – so the two footbridges that link them suggest reunification.

Even the roof has an ulterior motive. This is made up of a concrete grid, which links it with the facades and provides a cohesive shell. "It was important for us that the building be one whole, to give a sense of unity," says Melcher.

A generous cantilevered roof marks the entrance to the building, which contains more than 900 offices and meeting rooms. Inside, the rotunda provide relief from the straight lines of the enveloping walls. Each is 13 m in diameter, echoing the bend of the River Spree outside, and each is highlighted by strips of lights, which makes them look like a set from the classic German sci-fi film Metropolis.

The committee rooms, designed to accommodate the large round tables contained within, face a vast eight-storey hall topped by a glass ceiling. Open galleries on seven levels connect the office areas with the committee meeting rooms.

Outside the atrium the blocks are linked by a concrete lattice. Melcher says she chose the brightest white concrete available for this to give a sense of lightness and reflect the natural light that pours into the structure.