It is 8.00 a.m. in the Paris Metro. Packed. The strapontins are folded up to fit more standing commuters. One sways, everybody sways; it would be impossible to fall down. There is an old joke about a standing passenger who died at Pont de Sèvres, but nobody discovered until Chaussée d’Antin, when the people around him got out. In the mornings everyone is a zombie. A great experiment would be to replace half a carriage with store-window mannequins, as if anyone would notice. There is a kind of unwritten law which says that you must not look at another commuter’s…