France’s prime minister insisted Sunday that the government’s plan to raise the retirement age from 62 to 64 is “no longer negotiable,” further angering parliamentary opponents and unions who plan new mass protests and disruptive strikes this week. In an interview with France-Info radio broadcast Sunday, Prime Minister Elisabeth Borne said the age “is no longer negotiable.” A union-led online petition against the retirement plan saw a surge in new signatures after Borne’s comments.