Key shape in Olivier Rousteing’s autumn/winter collection was high-waisted trousers and nipped-in jackets in colours the late designer would have approvedFor his show at Paris fashion week, Balmain’s Olivier Rousteing paid homage to Yves Saint Laurent in an autumn/winter collection that channelled the late designer’s seventies and eighties work with all the attendant glamour, seduction and vibrant colours.