Assistant to hard-left parliamentarian among those held over fatal attack on 23-year-old during protest in Lyon

French authorities have arrested 11 suspects over the killing last week of a far-right activist, including an assistant to a hard-left member of parliament, a prosecutor and an informed source said.

Quentin Deranque, 23, died after sustaining a severe brain injury when he was attacked by at least six people on the sidelines of a far-right protest against a leftwing politician speaking at a university in the south-eastern city of Lyon.