La Bataille des couleurs

Weeks after approving the design, Georges Pompidou's office sent his culture minister a note: the model was white, and he wanted well-known colourists brought in. The original is in this show. His own idea, from Braque's lithographs, was light brown and blue. In a city of grey zinc and beige stone, the president's pick was brown.

You start with the fight, 1971 to 1977, in drawings, photographs, unpublished documents and a materials library. Vasarely wanted a gold and blue frame; after the architects' first pop palette, sixteen proposals came and went. Piano and Rogers answered with a code (blue for air, green for water, yellow for electricity, red for moving people and goods), invented, Piano now says, to protect their pop colours. The second room carries it down to tables, lamps, buckets and Michel Cadestin's steel-wire chair.

It's an archive show about a building, with no paintings. Entry is free, subject to space, 11am to 7pm, closed Tuesdays, at 50 rue Rambuteau, until 24 December.